JPS5849286A - Small sized serial printer - Google Patents

Abstract

PURPOSE:To securely accomplish returning operation of the titled printer to the home position of a carriage by a simplified construction so as to release locking state of the carriage to which a returning force is furnished by a spring and a cam member with a specific means. CONSTITUTION:When a carriage 12 comes to the extreme left end, a cam plate 22 is rotated counterclockwise so that the locking of an arm 32 of the carriage 12 and a protrusion 26 of the cam plate 22 is released, then the carriage 12 is returned to the right end by the tensile force of a return spring 29. When the carriage 12 returns to the home position, the locking of a bend 53 and a protrusion 54 is released and the cam plate 22 returns to the original state. When the carriage 12 is returned on the way, rotation of a hammer 18 is counteracted by a protrusion 16e of a chassis 16a of a printing type drum, and arm 18b does not move but a protrusion 23 runs away and pushes the cam plate 22, thereafter like the above, the carriage 12 is returned to the home position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized serial printer, and more particularly to a small-sized serial printer having a type drum that rotates about an axis perpendicular to the digit direction of printing paper.

Conventional serial printing type printers place the type drum vertically relative to the printing paper, that is, with the rotation axis horizontal, and print by the rotation, stop, impact, and carry operations of the type drum. The paper feed operation was performed after one line of printing was completed.

On the other hand, a serial printer is known in which a 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.

The carriage of this type of small serial printer is normally given a tendency to move toward the home position by a spring force. Several mechanisms have been proposed in which the carriage is returned to its home position after printing is completed using a spring force, but all of these mechanisms are complex and prone to malfunctions, so there is still room for further 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 to be able to reliably return the carriage to the home position with a simple structure.

In order to achieve the above object, the present invention provides a protrusion on the back surface of the base of the type drum provided on the carriage, which is provided with a return force by a spring, and arranges a cam member along the reciprocating path of the carriage. , a structure is adopted in which when one end of the printing hammer engages with a protrusion on the base of the type drum, the other end of the printing hammer pushes down the cam member to disengage the carriage and the cam member.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 schematically shows the overall structure of a small-sized serial printer according to the present invention. The small-sized serial printer according to the present invention is assembled on the basis of a housing-like frame l.

A motor 2 and a solenoid 3 that serves as a trigger when driving a control mechanism to be described later are attached to one end of the frame l. 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. The rotating shaft 6 is parallel to the output shaft 4.
is rotatably supported on a frame 1, and a belt 8 is stretched between a pulley 7 fixed to the outer end of the rotating shaft 6 and transmits the rotation of the motor 2. Inside the pulley 7, a tacho-generator coil IO having a tacho-generator magnet 9 which rotates together with the rotary shaft 6 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 1 is installed in the middle of the rotating shaft 6
1 is fixed, and the worm gear 11 is attached to the frame l.
It is rotatably supported 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, the carriage 12 is partially provided with a pulse signal detection contact piece 14, the tip of which engages with a protrusion 13a protruding from the side surface of the drum gear 13. I am placed in a position where we can meet each other.

The drum gear 13 is connected to a guide shaft 15.1 as shown in FIG.
A type drum 16 is rotatably supported on the upper side of the carriage 12 coaxially with a drum gear 13. The type drum 16 has a cylindrical base 1 as shown in FIG.
6a, and a type belt 16b for numbers and a type belt tec for symbols are wrapped around each other. It is facing inside. It also has a blank printed area for two characters.

A printer unit 17 is arranged above the type drum 16. The /\mma unit) 17 consists of a /\mma 18 located on the lower side for printing numbers, and a hammer 19 for printing symbols located on the upper side, both of which are each formed approximately in a V-shape as shown in Fig. 6. The base thereof 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 tip of the other arm 18b of this hammer 18 is connected to the rotation shaft 6.
The cross section extending horizontally between the motor 2 and the motor 2 along the L-shaped cam plate 22 faces a position where it comes into contact with a protrusion 23 protruding inside the base of the vertical portion 22a of the L-shaped cam plate 22.

The symbol printing hammer 19 is fitted into the type drum 16 by bending the tip of one arm 19a, and a roller 24 is attached to the tip of the hammer 19 at a position below the roller 21 and facing the symbol type belt 16c. is freely rotatable on the shaft. The tip of the other arm 19b is attached to a protrusion 25 located above the protrusion 23 of the vertical portion 22a of the cam plate 22.
It is placed in a position where it can be engaged with. Note that these protrusions 23 and 25 have a simple triangular cross section, and are configured so that the arms 18b and 19b can ride on them 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 knit 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, an ink roller 27 is rotatably supported on the carriage 12 near the type drum 16, as shown in FIG. 1, 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 platen 22c protruding from its lower end.
- It is set so that it can rotate freely within a fixed angle range, and a spring (not shown) provides a clockwise rotation habit 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 inside of the platen 30 along with a guide 31 having a groove, and is fixed to the other side plate 1a, so that the carriage 12 has a tendency to move to the right in the middle of FIG. However, when the claw 32a of the carriage 12 engages 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 connected to a shaft 34.
It is rotatably supported on the shaft.

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. It is given the habit of turning in the middle counterclockwise direction. The tip 35a of the control lever 35 faces the side of the carriage 12 at a position where it can engage with rack teeth 37a of a rack plate 37 arranged parallel to the horizontal portion 22b of the cam plate 22. Further, the drum gear 13
The rack plate 37 can also engage with the rack teeth 37a.
is rotatably supported within a certain angular range via a shaft 3B of the right side plate 1b in FIG.

As shown in FIG. 1, this rack plate 37 is generally formed into a mouth shape as a whole, and passes outside the right side plate 1b, passes under the platen 30, and is guided 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. Also,
A lever lever 39 is integrally formed on the side plate 1b side of the rack plate 37 at a position beyond the shaft 38, and a spring 40 is installed between its tip 39a and the upper end of the side plate 1b.
is stretched, and the entire rack plate 37 is given the habit of rotating clockwise in FIG. A protrusion 39b protruding from the L side of the distal end of the rack plate lever 39 is in contact with the distal end of the armature 41 of the solenoid 3.

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

The clutch gear 43 has a boss portion 43 as shown in FIG.
A coil spring 45 constituting a spring clutch is wound around a, one end 45a of which is fixed to the PF (paper feed) worm 46 side, and the other end 45b is fixed to the outside from the bottom of the PF worm 46. It is in a state where it can be engaged with the tip 48a- of the PF lever 48, which is rotatably supported near the clutch gear 43 via a shaft 47. The PF worm 46 is formed in a cylindrical shape, is fitted on the outside of the coil spring 45, and is rotatably supported on the shaft 44, as shown in FIG.

As shown in FIG. 9, the worm portion 46a of the PF worm 46 meshes with a PF gear 49, and this PF gear 49 is fixed to a shaft 51 that is integrated with a rubber roller 50 that sends out printing paper. 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. End 53a
, 53b are in a position to be engaged with a protrusion 54 protruding from the right end of the cam plate 22.

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 in FIG. 1 is caused by the pulley 5. Belt 8. It is transmitted to the drum gear 13 via the pulley 7, rotating shaft 6, and worm gear 11, and the type drum 16 integrated therewith is continuously rotated clockwise in FIG.

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
Since the drum gear 13 is in a fixed state, the drum gear 13 moves forward against the tensile force of the return spring 29 due to its rotational force, and the type drum 16 moves to the left in FIG. 1 while rotating.
A movement is held.

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 projection 23 of the cam plate 22, and the hammer 18 is rotated counterclockwise in FIG. 6, and the roller 21 pushes the protrusion 16d on the back side of the type bell) 16b, so that the selected type on the type bell) 16b pops out toward the printing paper P side and reaches the platen. 3
Printing is performed by pressing it to 0. At this time, if the surface of the pressed letters deviates even slightly from the printing paper P, dirt and ghosts will occur during printing and L will be scattered.
It is preferable to arrange the platen 30 at a position where the extended surfaces of the platen 30 are in contact with each other. By arranging them in this way, it is possible to perform printing while making complete rolling contact with the selected letters of the letter bell 16b 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 and the type belt 16b
returns to its original state as shown in FIG. 11, and printing of one digit is completed. At this time, if the solenoid 3 is left on, the rack plate 37 and drum gear 13 will not come apart, 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. Tip 35
a is engaged and the state shown in FIGS. 13 to 14 is reached, the drum gear 13 idles and the carry-up movement of the carriage 12 is stopped. At this time, the claw 32a of the carriage 12 is caught on the protrusion 26 of the cam plate 22, and the return spring 2
Even though the tensile force of 9 is applied, the carriage 12 does not return to its original state.
stops at that position.When the 0th order printing character is selected, the solenoid 3 is turned on and the same operation as described 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. When the control circuit turns on the solenoid 3 based on these two signals, the armature 41 moves the rack plate lever 39.
, the rack plate 37 is rotated counterclockwise in FIG. 1 about the shaft 38, and the rack plate 37 is placed on top of the fourth
The state shown in the figure changes to the state shown in FIG. 1O. 1st
When the rack teeth 37a mesh with the drum gear 13 and the carriage 12 begins to move in the state shown in Fig. Even if the energization is stopped, the engagement between the 8-35 and the rack teeth 37a does not occur.
After completing printing for one digit, the carriage 12 stops only when the state shown in FIG. 14 is reached. That is, the role of the control lever 35 is to prevent the rack teeth 37a from disengaging from the dry gear 13 during printing, and to ensure that printing for one digit is performed reliably.

The purpose is to prevent the carriage 12 from overrunning.

Next, the selection operation of symbol digit printing and i-character 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, when the carriage is viewed from the back side, the drive gear 33 and clutch gear 43 are engaged with each other and rotate as shown in FIG. in a state.

In this state, one end 45b of the coil spring 45 is engaged with the tip 48a of the PF lever 48, and the coil spring 45 is in a relaxed state, so the rotation of the clutch gear 43 is not transmitted to the PF worm gear 46. When the carriage is at the home position, the printing solenoid 3 is energized for the first time, carrying is performed as described above, and printing is simultaneously performed. At this time, the projection of the cam plate 22 is moved as shown in FIG. There is only one upper protrusion 25 that engages with the hammer 19 for symbol printing, and there is no protrusion 23 on the lower side of the protrusion 25 so that it does not engage with the hammer 18 for number printing. - Therefore, the first print is always a symbol, and during carrying, the protrusion 12a of the carriage 12 engages with the other end 48b of the P and F levers 48, and the PF lever 4B is rotated counterclockwise in FIG. When the one end 45b of the coil spring 45 and the one end 48a of the PF lever 48 are disengaged, and the state shown by the chain line in FIG. . However, since the protrusion 12a of the carriage immediately stops contacting the PF lever 48 and passes, the PF/<-49 immediately returns to its original position due to the force of a spring (not shown).
When the PF worm 46 rotates once, the one end 48a engages with the one end 45b of the coil spring 45 again, so the coil spring 4
5 is loosened, 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 rotates the printing paper P.
Feeds the paper by half a pitch.

In this way, the previously printed symbol is lifted to the same level as the next number to be printed, thereby eliminating the need for the downward movement of the type drum during printing, as is often the case with typewriters. and can be printed on the same line.

By the way, when printing is performed sequentially in this way and all the digits have been printed, carriage 1 is placed at the leftmost position in Figure 1.
2, as shown in FIG. 15, the claw 32a at the base of the arm 32 of the carriage 12 comes into contact with the protrusion 22d formed on the left end of the cam plate 22 toward the carriage, and a spring (not shown) comes into contact. The cam plate 22 is rotated counterclockwise as shown in FIG. 7 against the force. 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 engages with the protrusion 54 as shown in FIG. moves to the left in the figure, and the protrusion 54 is locked inside the bent portion 53a of the leaf spring 53, holding the cam plate 22 in that position. In this state, the arm 32 of the carriage 12 and the projection 26 of the cam plate 22 are disengaged, so the carriage 12 returns to the spring 26.
9 is pulled to the right end in FIG. 1 and returned.

In this pullback 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 4B is pulled back rapidly until the carriage 12
When the carriage 12 returns to the home position, the paper is fed a second time by half a pitch, and the paper is fed by a total of l pitches.

Further, when the carriage 12 returns to the home position, the protrusion 12b at the right end of the carriage 12 hits the tip 53b of the leaf spring 53 as shown in FIG.
3a and the protrusion 54 are disengaged, the cam plate 22 is rotated clockwise in FIG. 7 by a spring (not shown).

Return to original state.

In this way, one printing cycle is completed.

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

When the roller 21 of the hammer 18 turns on the solenoid 3 at the position of the protrusion 16e and tries to perform a printing operation, the rotation of the hammer 18 is blocked by the protrusion 16e, and the arm 1
When the protrusion 8b and the protrusion 23 meet, the arm 18b is moved.Contrary to the above, the arm 18b does not move and the protrusion 23 escapes, so the cam plate 2
2, the cam plate 22 is rotated in the same manner as described above, and as shown in FIG.
The carriage 12 returns to the home position and one printing cycle is completed.

Further, when only paper feeding is performed without printing, by turning on the solenoid twice for the protrusion 16e in the type drum 16, the paper is fed by one pitch and the carriage returns to the home position.

In addition, in the embodiment described above, when the type is divided in the circumferential direction of the type drum 16, the number of teeth of the drum gear 13 is the same number of 1 to 1, but the number of teeth may be an integral multiple of the number of divisions of the type drum. .

Furthermore, in the above embodiment, a number printing bell) 1
6b and symbol printing bell) 16c are separate parts, but they may be wrapped as one body.Furthermore, the number of printing belts can be increased to, for example, three rows, and the ink rollers 27 can be used in two colors, red and black. It is also possible to arrange them one above the other so that two-color printing can be performed.

As is clear from the above description, according to the present invention, the engagement between the carriage and the cam member, which is provided with a restoring force by a spring, is achieved between the protrusion on the back surface of the base of the type drum provided on the carriage and one end of the hammer. To provide a compact serial printer which can surely return the carriage to its home position with an extremely simple structure, since the cam member is released by tilting the cam member with the other end of the hammer when engaged. I can do it.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 is a perspective view explaining the overall structure, FIG. 2 is a bottom view explaining a group of gears attached to the back side of the carriage, and FIG. FIG. 4 is a bottom view of the carriage; FIG.
The figure 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, FIG. 7 is a plan view illustrating the return movement of the carriage, and FIG. 8 is a spring clutch. 9 is a side view explaining the paper feeding mechanism, FIG. 1O is a side view explaining the operation of the carriage drive control mechanism, and FIGS. 11 and 12 respectively show the printing operation of the hammer. Explanatory drawings, FIGS. 13 and 14 are explanatory views showing the interlocking relationship between the printing paper supply lever, the drum gear, and the rack plate that is a control member, and FIG. 15 is a side view of the main parts illustrating the carriage return operation. , FIGS. 16 to 19 are explanatory diagrams showing the control operation of the cam member during the digit return operation, respectively. 2...Motor 3...Solenoid 6...
・Rotating shaft 11... Worm gear 12...
Carriage 13... Drum gear 16... Type drum 113a... Base 16b... Type belt for numbers 18c... Type belt for symbols 18... Hammer for printing numbers l8... Hammer for printing symbols 22...Cam plate 23.25...Protrusion 33
...Drive gear 37...Rack plate 39...
Rack plate lever 43...Cler 2nd gear 45...
Coil spring 4B...Paper feed worm 48...
Paper feed lever 49... Paper feed gear 50... Rubber roller Figure 1 Figure 2

Claims (1)

[Claims] A small serial printer comprising a type drum that rotates around an axis perpendicular to the digit direction of printing paper, and a carriage that conveys the type drum in the printing digit direction, the type drum having a cylindrical base; The type drum is wrapped around the base and is equipped with a plurality of type belts made of elastic members on which type characters such as numbers and symbols are placed on the surface.
The inner nose of the base has a protrusion that engages with one end of the hammer, and when the protrusion of the hammer and the protrusion engage, the cam member and the carriage engage with the other end of the hammer. A small serial printer characterized in that the carriage is disengaged and the carriage is returned to the home position by spring force.