JPS5953877B2 - printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing machine for a data processing device,
Provided is a printing machine that can easily attach and detach printing materials with uneven thickness, such as horizontally folded bank passbooks, vertically folded passbooks, or slips, and that can print with good print quality on the printing materials. This is what we intend to provide.

Conventionally, printing machines that satisfy the above-mentioned requirements include those using a type bar system or those using a sindal element system, but both have a drawback of slow printing speed.

Here, the wire impact dot matrix method can be mentioned as a printing machine that can display a large number of characters, has a fast printing speed, has low noise, and is inexpensive. In this case, it is necessary to maintain the gap between the print head and the surface of the printing object, that is, the printing surface, at about 0.3 mm to 0.6 mm, and it is necessary to maintain the gap between the print head and the surface of the printing object, that is, the printing surface, at about 0.3 mm to 0.6 mm. It is difficult to print on any of the duplicated copy slips. As a means to eliminate such drawbacks and to easily attach and detach the printing object, the platen is moved backward to release the printing object when attaching and removing the printing object and when starting a new line, and the platen is moved forward during printing. , the structure for pressing the printed surface against a receiving member for keeping the printed surface in a proper printing position and the fact that the platen is divided into three parts have already been explained in JP-A-51-19609. There is. According to the explanation in JP-A-51-19609, platen C
In other words, in order to support the center platen unit so that it can approach and move away from the printing body, the same method as the support method for the platens at both ends is used.
The platen lever C is rotatably supported at the other end of the platen lever C fixed to the platen C. Therefore, due to accidental twisting of each platen lever, it becomes difficult to bring the sliding surfaces of each platen into uniform contact with each other, and as a result, the sliding resistance between each platen becomes large and platen C cannot move independently. At the same time, there are large gaps between each platen.
When printing in the above-mentioned gap of a thin slip, it is not possible to print in the gap, especially if the printing method is an impact type dot tomato print method, there is a risk of perforation of the slip, and furthermore, the printing may be perforated. The font may also be damaged. Another drawback is that the exclusive space for the means for supporting the platen C becomes large. The above drawbacks are more or less observed when the platen C is supported from the outside, regardless of whether or not the platen C is swingably supported. The present invention was invented in view of the above matters,
It is an object of the present invention to achieve good printing on printing materials with uneven thickness, such as horizontally folded bank passbooks and vertically folded passbooks, single slips, or stacked slips. To obtain a printing object holding device in a printing machine that can print with high quality and has excellent reliability and durability.

The gist of the present invention for achieving the above object is that the platens at both ends of a platen divided into three parts are supported so as to be close to and separated from the printing body, and the central platen is supported at both ends of the platen. The device for holding the printing medium in the printing machine is supported by the platens at both ends so as to be able to move in the same direction as the platen.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a wire impact dot matrix printing machine will be described in detail below with reference to the drawings.

Figure] is a schematic diagram showing the overall appearance of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an internal structure showing the internal structure of FIG. 3 is an explanatory view showing the operating state of the structure shown in FIG. 2, and FIG. 4 is a sectional view of FIG. 3. FIG. 5 is a detailed view of the platen portion, and FIG. 6 is a sectional view of FIG. 3 showing the operating state of the platen locking lever. In Figure 1, 1
is a frame, which forms the base of the structure of this device.

2 is an electric motor that serves as the prime mover of this device, and is a part 1a of the frame 1.
The rotary output shaft 2b (Fig. 2) rotates in the direction of the arrow when a voltage is applied to the lead wire 2a. It is configured as follows.

A gear A 3 is fixed to the rotation output shaft 2b of the electric motor 2.

Reference numeral 4 denotes a paper table, which is a guide member for a printing medium 7 and has a space in which a platen 50 (described later) operates, and is fixed to the frame 1.

Reference numeral 5 denotes a receiving member, which is a positioning member for keeping the printing surface of the printing object 7 at a constant distance from the printing head 8;
is fixed to.

Reference numeral 6 denotes a paper guide (see FIG. 3), which is a member for guiding insertion of a printing medium provided perpendicularly to the printing line, and is fixed to the paper table 4.

Reference numeral 7 denotes a printing medium to be printed by this printing machine, and in the example shown in FIG. 3, it represents a bank passbook, etc., and has a folded part 7a in the center.

Reference numeral 8 denotes a member for printing on the printing object 7, which is a wire impact dot matrix printing head, and is fixed to a carriage (not shown), which is connected to a guide rail ( (not shown) so as to be able to move freely in the printing line direction, and is connected to a driving means (not shown) for the movement.

Reference numeral 9 denotes a transmission shaft, which is rotatably supported by the frame 1.

Numeral 10 is fixed to the transmission shaft 9 by a so-called spring latch using a spring (not shown), and supports a gear BlOa serving as an input end so as to be able to rotate coaxially with the transmission shaft 9. meshes with the gear A3 and rotates with the rotation of the rotary output shaft 2b of the electric motor 2,
Further, on the same axis, adjacent to the gear BlOa, a pawl plate 10b having two pawls serving as control ends is rotatably supported.

Furthermore, although not shown, a spring is wound around the shaft protruding from the gear BlOa and the shaft fixed to the transmission shaft 9, one end on the gear AlOa side is fixed to the pawl plate 10b, and one end on the transmission shaft side is fixed to the claw plate 10b. One end of the is fixed to a shaft fixed to the transmission shaft. That is, if the rotation of the claw plate 10b is blocked while the gear BLOa is rotating with the rotation of the rotational output shaft 2b of the electric motor 2, the rotation of the gear BLOa is transmitted to the transmission shaft 9, and the blocking of the claw plate 10b is caused. When released, the rotation of the gear BlOa is transmitted to the transmission shaft 9 by the tightening force of the spring, and the transmission shaft 9 is configured to rotate together with the gear BlOa. 1] is the clutch trigger shaft, which is part 1 of the frame 1.
It is planted in a.

12 is a trigger lever, which is connected to the clutch trigger shaft 11;
A spring clutch 10 is fitted to the tip so that it can swing freely.
A bent portion 12a for locking the claw plate 10b is formed, and an operation pin 12b for operating the trigger lever 12 body from the outside is planted in the center.

A trigger lever return spring 13 is suspended at one end by the frame 1 and at the other end by the trigger lever 12, and urges the bent portion 12a of the trigger lever 12 in a direction to engage the claw plate 10b. .

] 4 is a trigger solenoid fixed to the frame 1,
When a voltage is applied to the lead wire 14b of the coil] 4a,
The armature 14d swings about the armature shaft 14C and is configured to be attracted to the coil 14a side, and a groove formed at the tip of the armature 4d is loosely fitted into the operating pin 12b of the trigger lever 12. The lever is biased by the trigger lever return spring 13 in a direction opposite to the attracting direction, and comes into contact with a stopper (not shown). A worm 15 is fixed to the transmission shaft 9.

A camshaft 16 is rotatably supported by the frame 1.

A worm wheel 17 is fixed to the camshaft 16 and is configured to mesh with the worm 15 and rotate the camshaft 16 in accordance with the rotation of the transmission shaft 9.

Reference numeral 18 denotes a rotary cam (a rotary cam of the same shape) which is offset by 60 degrees from 8a, and is connected to a cam bush 18b and a connecting pin 18C.
Further, the force lever 18b is fixed by the camshaft 1.
6 and is configured to rotate together with the camshaft 16.

Reference numeral 19 denotes a detection auxiliary member board, which is fixed to the camshaft 16 via a bush 19a and is configured to rotate together with the rotary cam 18.

Magnets 20 and 22 are fixed to the disk surface of the detection auxiliary member substrate 19 at an interval of 180° by coupling pins 21 and 23, respectively.

Reference numeral 24 denotes a platen position detection member holder, which is fixed to the frame 1.

Reed switches 25 and 26 are attached to the platen position detection holder 24.
Connect one terminal of each of 6 to each other to form a lead wire 27,
It is connected to a control circuit (not shown).

The other terminals of the reed switches 2, 5 and 26 are connected to a control circuit (not shown) via lead wires 28 and 29, respectively. Reference numeral 30 denotes a platen push-up camshaft, which is fixed to a portion 1C of the frame 1.

Reference numeral 31 denotes a platen push-up cam, which is fixed to the platen push-up cam bush 32.
2 is fitted into the platen push-up camshaft 30 so as to be able to swing freely.

In addition, the platen pushing cam 31 has a follower roller 33 rotatably attached to one end by a roller shaft 34, and a cam portion 31a for pushing up a lifting roller 45, which will be described later, is attached to the other part. It is formed. Reference numeral 35 denotes a platen push-up cam return spring, one end of which is suspended from the other end of the platen push-up cam 31, and the other end of the platen push-up cam return spring suspended from a portion 1e of the frame 1. The cam 31 is urged in the direction of the arrow, and the follower roller 33 is brought into contact with the rotating cam 18.

Reference numeral 36 designates a leaf spring, one end of which is attached to one end of part 1C of the frame body with a clamping plate 37 and a connecting pin 38, and the other end is attached to one end of a lifting plate 43 with a clamping plate 41 and a connecting pin 42. The center portion is sandwiched between sandwiching plates 39 from both sides and crimped and clamped using a connecting pin 39.

A leaf spring 36 is also attached in a similar structure between the other end of the portion 1C of the frame 1 and the other end of the lift plate 43. Further, a lifting roller shaft 44 is installed on the moving plate 43.
A lifting roller 45 is rotatably attached to the lifting roller shaft 44. Reference numeral 46 denotes a platen support plate, which is individually attached to the lift plate 43 with a connecting pin 47.

Reference numeral 48 denotes a spring-loaded pin, which is set up on the platen support plate 46.

49 is a platen return spring, one end of which is connected to the spring hook pin 48.
The other end is suspended on a part 1d of the frame 1, and urges the combination of the platen support plates 4 and 6 and the lifting plate 43, and the lifting roller 44 moves the cam of the platen pushing cam 31. Part 31a
is pressed against.

50 is a platen left unit, which is attached to the platen support plate 46.
In the state shown in FIG. 4, that is, in the position of the platen support plate 46 described above, its upper surface, that is, the surface in which the printing object is pressed, is flush with the upper surface of the paper table 4. A spring pin 51 is installed at one end.

Further, a platen auxiliary body 52 is fixed to the lower part. 5
3 is a platen right unit, which has a spring pin 54 planted at one end and a platen auxiliary body 55 fixed to the lower part.

The combination of the right platen unit 53 is connected to a separate drive mechanism and support mechanism similarly to the combination of the left platen unit 50 described above, and is configured to be driven by the driving force of the rotating cam 18a. The upper surface of the left platen unit 50, that is, the surface against which the printed object is pressed, is flush with the upper surface of the right platen unit 50. 56 is the central platen unit, which includes guide plate A6O and guide plate B6.
A support pin 57 and a spring hook pin 58 are loosely fitted into the square hole 1 with a slight gap and are used to support the guide plate A6O.
A positioning body 59 is fixed to the lower surface, and both ends of the guide plate A6O and the guide plate B6l are arranged so that one end of the platen left unit 50 and the platen right unit 53 are placed between the square cuts. Fit loosely with a slight gap,
Working together with the left platen unit 50, the right platen unit 53, and each platen auxiliary body 52, 55, the central platen unit 56 is guided so that it can move straight upward and downward and not tilt in any direction. .

A left platen spring 62 is suspended between the spring hook pin 51 of the left platen unit 50 and the spring hook pin 58 of the center platen unit 56.

A right platen spring 63 is suspended between the spring hook pin 54 of the platen right unit 53 and the spring hook pin 58 of the center platen 56.

Although not shown, the four platen springs, which are similarly suspended at each symmetrical position, work together to bias the central platen unit 56 upward, and the positioning body 5
9 is in contact with the platen auxiliary bodies 52 and 55, and the upper surface of the central platen unit 56, that is, the surface against which the printed object is pressed, is flush with the upper surfaces of the left platen unit 50 and the right platen unit 53, respectively. That is, the central platen unit 56
are on the same plane if the platen units on both sides are on the same plane, but when one of the platen units is lowered, the center platen unit 56 is pushed down by the lower platen unit, and the center platen unit 56 By strongly pressing down on the pressing surface of the printing object,
The central platen unit 56 is configured to be depressed by four platen springs. 64 is the central platen unit locking lever, and the locking lever bushing 65
The locking lever bush 65 is rotatably supported by a locking lever shaft 66 that is mounted on a portion 1a of the frame 1.

The central platen unit locking lever 64 has a bent portion 64a formed at one end, a locking portion 64b at the other end, and a spring hook portion 64C formed near the locking portion 64b. A locking lever spring 68 is suspended between the spring hanging portion 64C and a spring hanging pin 67 that is set up on a portion 1f of the frame 1, and biases the central platen unit locking lever 64 clockwise. , the bent portion 64a is in contact with the follower roller 33. The platen push-up cam 31 is the third
In the state shown in the figure, that is, in the state in which the top surfaces of the platens 50, 53, and 56 are in the same plane as the top surface of the paper tray 4, the central platen locking lever 64 is in the state shown in FIG.
b is slightly separated from the positioning body 59 fixed to the central platen unit 56. Next, the functions of the above structure will be explained based on the respective drawings.

When printing on a printing medium that has different thicknesses in the printing direction, such as a vertically folded passbook, place the printing medium 7 on the top surface of the paper table 4 and align the right end along the paper guide 6, as shown in FIG. When you insert
A paper feeding device (not shown) moves the desired position, that is, the line to be printed, to the print body 8. The vehicle is sent directly below the trajectory of the vehicle. The platen is set in advance so that the central platen unit corresponds to the thickness changing portion 7a of the printing medium 7.

After the printing object 7 is positioned at the desired position, a control circuit (not shown) connects the lead wire 2 of the motor 2 in FIG.
A voltage is applied to a, and the rotation output shaft 2b starts rotating.
Therefore, the gear A3 fixed to the rotating output shaft 2b also rotates, and accordingly, the gear BlOa of the spring clutch 10 rotates.
rotates clockwise. However, as explained in the structure of the decoction,
Since the spring clutch is in the 1-degree disconnected state, the transmission shaft 9 does not rotate. Subsequently, a voltage is applied to the lead wire 14b of the trigger solenoid 14 by a control circuit (not shown).
The armature 14d swings around the armature shaft 14C by being attracted to the coil 14a side, and moves the trigger lever 12 to the clutch trigger shaft 11 via the operating pin 12b set on the trigger lever 12. The trigger is rotated about the center of rotation against the biasing force of the trigger return spring 13.

Therefore, the bent portion 12a of the trigger lever 12 releases the pawl plate 10b of the spring clutch 10, bringing the spring clutch 10 into the connected state. In other words, power can be transmitted at any time using weak electric power, and it can be started without noise or impact. Spring clutch 1
0 becomes the connected state, the rotation of the gear BlOa rotates the transmission shaft 9 via the spring latch 10, causing the worm 15 fixed to the transmission shaft 9 to rotate clockwise.

The rotation of the worm 15 causes the worm wheel 17 and the camshaft 16 fixed to the worm wheel 17 to be rotated.
rotates counterclockwise.

Therefore, the rotating cams 18, 18 fixed to the camshaft 16
a and the detection auxiliary member substrate 19 also rotate together. Rotating cam 1
The follower roller 33, which is half the rotation of 8, moves its abutting portion from the large-diameter portion of the rotating cam 18 to the small-diameter portion, and the platen push-up cam 31 rotates in the direction of the arrow, that is, clockwise. move. That is, when the platen push-up cam 31 in FIG. When the platen support plate 46 is pushed up against the biasing force of the platen return spring 49 and the rotating cam 18 continues to rotate and reaches the state 18-1, the follower roller 33 becomes the state 33-1. , the cam portion 31a is 31a
-L lifting roller 45 is in the state 45-1. The above operation and state will be explained with reference to FIG.
1a. The lifting plate 43 and platen support plate 46, which are pushed up via the lifting roller 45, are made up of two upper and lower plates, one end of which is fixed to the part 1C of the frame 1, and the center part of which is held between the holding plates 39. It is supported by a leaf spring 36, that is, a so-called parallel spring, and the leaf spring 36 is bent at the free portions of both ends which are held by the holding plate 39. Due to this support structure, there is no unnecessary gap in the support intervening part, so it does not swing back and forth or from side to side due to backlash, and since there are no sliding parts, there is no need for lubrication and there is no wear, making it durable. .
The platen left unit 50 fixed to the platen support plate 46 is connected to the cam portion 31a of the platen push-up mechanism 31.
By the pushing-up operation, the object to be printed 7 is raised with the object 7 placed on the upper surface, and the upper left surface of the object to be printed 7 is pressed against the receiving member 5 and stopped.

Similar to the above-described operation of the left platen unit 50, the right platen unit 53 is simultaneously operated by the rotary cam 18a, and the right upper surface of the printing medium 7 is pressed against the receiving member 5 and stopped.

However, as shown in FIG. 3, since the printing medium 7 is thinner on the left side and thicker on the right side, the platen left unit 50 approaches the receiving member 5 and rises upwards, but the platen right unit 50 rises upward. 53 is located further away from the receiving member 5 and remains below the platen left unit 50. The center platen unit 56 cannot be above the upper surface of the lower platen unit, that is, the right platen unit 53, due to the positioning member 59 to which the upper surface is fixed. However, since the stepped part or folded part of actual bank and post office passbooks, etc. protrudes slightly downward, the upper surface of the platen center unit 56 is relatively biased against the urging force of the left platen spring 62 and the right platen spring 63. The platen right unit 53 is pushed down and remains below the upper surface of the platen right unit 53. In this way, the upper surface, that is, the printing surface, of the printing object 7, which has a thickness difference on the left and right sides, becomes the same plane, and it becomes possible to perform printing by the printing object 8 moving straight. When the platen is in this state, the rotating cam 18
The magnet 20 fixed to the detection auxiliary member board 19, which rotates together with the reed switch 26, approaches the reed switch 26, closes the contact of the reed switch 26, and connects the lead wire 27 to the lead wire 28.
A conductive state is established between the two. That is, it is detected that the platen is ready for printing, and is transmitted to a control circuit (not shown) as a signal to bring conduction between the lead wires 27 and 28. The signal controls a control circuit (not shown).
stops the voltage applied to the lead wire 14b of the trigger solenoid 14. Therefore, the armature 14d and the trigger lever 12 are restored by the biasing force of the trigger return spring 13, and the bent portion 12a of the trigger lever 12 is
The pawl plate 10b of the spring clutch 10 is locked. Therefore, the spring clutch 10 is in the disconnected state 7, the transmission shaft 9 immediately tries to stop rotating, and the camshaft 16 also tries to stand still, but the rotating cam 18a and the detection auxiliary member board 19
The worm wheel cannot be stopped immediately due to the inertia of the
7 presses the worm 16 in the axial direction, and the worm 16 is supported by the frame 1. Therefore, the spring clutch 10 is not subjected to any undesirable forces, and the rotating cam 18a is stopped due to inertia without overrunning. At the same time, the electric motor 2 is controlled by a control circuit (not shown).
The voltage application to the lead wire 2a is also stopped, and the electric motor 2 also stops. Due to this stopping method, it can be stopped immediately at an appropriate time without impact or noise, and since the raised state of the platen, that is, the state in which printing is possible, can be determined, related operations with other mechanisms are guaranteed. The operation of the central platen locking lever 64, which operates together with the upward movement of the platen, will be explained with reference to FIG. As mentioned above, the rotating cam 18
As the follower roller 33 rotates, its contact portion moves from the large-diameter portion of the rotating cam 18 to the small-diameter portion.
The locking portion 64b is rotated clockwise by the biasing force 8, and the locking portion 64b comes into contact with the positioning body 59. Therefore, the follower roller 33
is further lowered, but the central platen locking lever 64 is
Stop at the position. On the other hand, the central platen unit 56 is
It continues to rise and stops with the stepped portion of the thickness of the printing medium 7 pressed against the receiving member 5 as described above. The position of the positioning body 59 when the central platen unit 56 is in the above position is
The locking portion 64b of the central platen locking lever 64 does not rise to the point where it comes out of the above-mentioned contact state and enters the lower part of the positioning body 59. That is, in this state, the center platen unit 56 is not locked by the center platen locking lever 64, so if it is pressed from the top surface, it will resist the urging force of the left platen spring 62 and the right platen spring 63. It is possible to press down. However, as shown in Fig. 3, since the printing object 7 is a passbook, the central flap part has the following markings.
Since there is no printing, it is possible to print by pressing. Further, as shown in FIG. 6, when the printing object 7 is thinner than the passbook, such as a thin single slip or a stack of several slips, the central platen unit 56 is close to the receiving member 5, so that it can be positioned easily. The body 59 is raised higher than when the printing object 7 is a passbook, the locking part 64b is crowded under the positioning body 59, and as the positioning body 59 is raised, the locking part 64b is moved to the right. When the central platen unit 56 stops and enters the state 56-1, the positioning body 59 becomes the state 59-1, and the locking portion 64b becomes the state 64-1.
The state becomes b-1. Therefore, the central platen unit 56
is locked with the upper surface of the object to be printed 7 pressed against the receiving member 5, so that the upper surface of the object to be printed 7 is at the position of the lower surface of the receiving member 5, and the platen left unit 50 and the platen right The parts pressed by the platens of the unit 53 and the central platen unit 56 are all on the same plane, and are held at positions suitable for printing by the printing body 8. Therefore, printing by the stamping method is possible at any of the above locations. In other words, if the printing object 7 has a thickness such that the locking portion 64b can engage with the positioning body 59, printing can be uniformly performed at any location. Subsequently, the reed switch 26 enabled the platen to print, and the control circuit (not shown)
The printing body 8 is run in the longitudinal direction of the platen, that is, along the printing line to perform a printing operation, and the printing body 8 prints on the printing medium 7.

When the printing operation is completed, a control circuit (not shown) applies a voltage to the lead wire 2a of the electric motor 2 in FIG. 2, and the rotational output shaft 2b starts rotating in the direction of the arrow.

Therefore, the gear A3 fixed to the rotating output shaft 2b also rotates,
Accordingly, the gear BlOa of the spring clutch 10 rotates clockwise. However, since the spring clutch is in the fractured state 7, the transmission shaft 9 does not rotate. A control circuit (not shown) then connects the lead wire 14 of the trigger solenoid 14.
When a voltage is applied to b, the armature 14d is attracted to the coil 14a side and swings around the armature shaft 14C, and the trigger lever 12 is actuated via the operating pin 12b set on the trigger lever 12. The clutch trigger shaft 11 is rotated around the clutch trigger shaft 11 as the center of rotation against the biasing force of the trigger return spring 13. Therefore, the bent portion 12a of the trigger lever 12 releases the pawl plate 10b of the spring clutch 10, and the spring clutch 10 is in the connected state.
When the spring latch 10 is in the connected state 7, the rotation of the gear BlOa rotates the transmission shaft 9 via the spring clutch 10, and when it is fixed to the transmission shaft 9, the worm 1
Rotate 5 clockwise. The rotation of the worm 15 causes the worm wheel 17 and the worm wheel 1 to rotate.
A camshaft 16 fixed to 7 rotates counterclockwise. Therefore, the rotating cam 18,1 fixed to the camshaft 16
8a and the detection auxiliary member substrate 19 also rotate together.

As the rotating cam 18 rotates, the follower roller 33 moves its contact portion from the small diameter portion of the rotating cam 18 to the large diameter portion,
The platen push-up cam 31 rotates in the direction opposite to the arrow.

That is, when the platen push-up cam 31 in FIG.
is lowered by the urging force of the platen return spring 49 via the lifting roller 45 while following the cam portion 31a. When the rotating cam 18 continues to rotate and reaches the state shown in FIG. 3, the platen pushing cam 31 and the platen support plate 46
, the platen left unit 50 is also in the state shown in FIG. Similar to the operation of the left platen unit 50, the right platen unit 53 is simultaneously operated by the rotary cam 18a.

Further, the central platen unit 56 is lowered together with the left platen unit 50 and the right platen unit 53 while maintaining the mutual relationship shown in FIG. 3, resulting in the state shown in FIG. The above explanation is for the case where the printing object 7 is thick, such as a bankbook, and the central platen locking lever 64 does not lock the central platen unit 56.

Next, the operation when the printing object 7 has a small thickness such as a single slip and the central platen locking lever 64 locks the central platen unit 56 will be described with reference to FIG.

As described above, the platen holds the thin printing object 7 between it and the receiving member 5, and the locking portion 64b of the central platen locking lever 64 is in the state 64b-1, and the positioning body 59 is in the state 59-1. It is locked in state 1. In this state, the rotating cam 18 rotates as described above, and the follower roller 33
rises, and when the platen push-up cam 31 rotates against the biasing force of the platen push-up cam return spring 35, the positive movement plate 43
, the platen support plate 46 attempts to descend following the cam portion 31a via the lifting roller 45 due to the biasing force of the platen return spring 49, but as described above, the center platen unit 56 does not lock the center platen. The lever 64 is locked and cannot be lowered. Therefore, as shown in FIGS. 3 and 5, the left platen unit 50 and the right platen unit 5, which are prevented from descending by the positioning body 56,
3 can't go down either. Subsequently, when the rotating cam 18 rotates and the follower roller 33 descends, the locking portion 64
b indicates that the central platen unit 5 is detached from the positioning body 59.
6. Platen left unit 50, platen right unit 53
is returned by the biasing force of the platen return spring 49, and the third
The state shown in FIG. 4, FIG. 6, and FIG. When the platen is in this state, the magnet 20 fixed to the detection auxiliary member substrate 19, which rotates together with the rotating cam 18, approaches the reed switch 25, closes the contact of the reed switch 25, and connects the lead wire 27. The lead wires 29 are electrically connected. That is, it detects that the platen 50 has descended to the lowest end and transmits it to a control circuit (not shown) as a signal that brings the lead wires 27 and 29 into a conductive state. The signal causes a control circuit (not shown) to trigger solenoid 1.
The voltage applied to the lead wire 14b of No. 4 is stopped.
Therefore, the armature 4d and the bent portion 12a of the trigger lever 12 engage the pawl plate 10b of the spring clutch 10. As a result, the spring clutch 10 is in the disengaged state 7, the transmission shaft 9 immediately stops rotating, and the camshaft 16 also comes to a standstill. In addition, by a control circuit (not shown),
The voltage application to the lead wire 2a of the electric motor 2 is also stopped, and the electric motor 2 also stops. Thereafter, the printed object is fed to a line feeder or ejected by a paper feeding device (not shown). As is clear from the above explanation, according to the support means for the central platen unit according to the present invention, each platen can be brought into close contact with each other without applying contact pressure, so that the independent operation of each platen can be performed smoothly. In addition, when printing is performed using the impact dot matrix method, there is no possibility of perforating the slip or damaging the printing head due to the gaps between the contact surfaces of the platen. It is possible to configure a printing medium holding device in a printing machine that occupies a small space and requires a small number of parts.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the overall appearance of an embodiment of the present invention. FIG. 2 is an explanatory diagram of an internal structure showing the internal structure of FIG. FIG. 3 is a diagram showing the operating state of the structure of FIG. 2. FIG. 4 is a sectional view of FIG. 3. FIG. 5 is a detailed view of the platen portion. FIG. 6 is a sectional view of FIG. 3 showing the operation of the platen locking lever. 5...Receiving member, 8.
...Printed body, 50...Platen left unit, 53...Platen right unit, 56...
...Central platen unit, 60...Guide plate A, 61...Guide plate B, 62...
Left platen spring, 63...Right platen spring.

Claims (1)

[Claims] 1 A printing machine that prints on printing materials such as bankbooks and slips, which includes a print head for printing on the printing material and a device for positioning the surface of the printing material at a predetermined position relative to the erroneous printing head. a receiving member; when printing, the surface of the printing object is held in a predetermined position by moving forward and pressing the printing object against the receiving member; and when conveying the printing object, a platen that retreats to release the printing material;
In the printing machine having the structure of the platen part a
a platen left unit that has a surface that supports a printing target and is supported so as to be able to move forward and backward, and c a platen right unit that has a surface that supports a printing target and is supported so that it can move forward and backward, and c the left platen unit. and the platen right unit, and has two shoulders that abut the back surfaces of the platen left unit and the platen right unit, respectively, and is flush with the two platen units when the shoulders are in contact with each other. a central platen unit having a surface forming the same shape; d; urging means for pressing the two shoulders of the central platen unit into pressure contact with the back surfaces of the left platen unit and the right platen unit; and e; A printing machine comprising: a guide plate for guiding the left platen unit and the right platen unit so that they can move in the same direction as the forward and backward movement directions of the left platen unit and the right platen unit.