JPH0694222B2 - Line thermal printer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a line thermal printer.

2. Description of the Related Art Conventionally, in order to bring the thermal head and the platen into contact with each other when printing and to separate the thermal head and the platen from each other when simply feeding the paper, either the platen or the thermal head is moved by a solenoid. There is a printer.

Problems to be Solved by the Invention However, in the line thermal printer, it is necessary to press the thermal head and the platen with a strong spring force so that the paper is brought into close contact with the thermal head evenly. A solenoid with a large capacity is required as a power source for separating the platen from the thermal head.
Because of this, the operating noise of the solenoid becomes loud, and
While the thermal head and the platen are separated from each other, it is necessary to maintain the energized state, which increases power consumption.

Also, the contact width between the thermal head and the platen is more than the width of the paper, but the contact pressure between the thermal head and the platen may be different on both sides in the width direction of the paper, which may adversely affect the print density and the paper feed. It is affecting.

Means: A pair of left and right movable bodies, which are rotatably held at both ends of the platen, are rotatably provided, respectively, and swing along the longitudinal direction of the platen about a fulcrum located opposite to the center of the platen. An oscillating body that moves is provided, and both ends of a pair of left and right ridges that urge the movable body toward the thermal head are fixed to both sides of the oscillating body and the movable body. A cam having a pressing portion for separating it from the head was rotatably provided, and this cam was connected to the motor via a clutch.

Therefore, the rotation of the motor is transmitted to the cam through the clutch, and the rotation of the cam causes the movable body to rotate to selectively bring the platen into contact with and separate from the thermal head. In addition, a load is applied to the motor when the platen is separated from the thermal head, but this load can be gently changed by the rotation of the cam, so that it is possible to reduce the capacity of the motor. Since the motor can be stopped at a desired position by the operation, the motor can be rotated only while the clutch is operated, and the power consumption can be reduced. Further, by using a motor as a drive source for bringing the platen into and out of contact with the thermal head, generation of operating noise is suppressed.

Further, a pair of left and right movable bodies independent of each other, which are rotatably held at both ends of the platen, are rotatably provided, respectively, and are arranged along the longitudinal direction of the platen about a fulcrum arranged opposite to the center of the platen. By providing an oscillating oscillating body and fixing both ends of a pair of left and right ridges for urging the movable body to the thermal head side to both sides of the oscillating body and the movable body, the left and right sides of the oscillating body are rotated. Balance the strength of the spring and equalize the pressure contact force at the left and right ends of the platen to the thermal head.

Embodiment An embodiment of the present invention will be described with reference to the drawings. First,
FIG. 7 shows the overall configuration. Reference numeral 1 denotes a magnetic recording unit, which is composed of a plurality of conveying units 5, 6, 7 composed of a feed roller 3 connected to a motor 2 and another feed roller 4, and a magnetic head 8 for recording. , And a magnetic head 9 for reading. On the downstream side of the magnetic recording unit 1, a feed roller 11 and a pinch roller 13 supported by an arm 12 are provided to face each other with a guide plate 10 in between. Arm 12 has axis 14
It is rotatably held by the spring, is biased counterclockwise by the spring 15, and is further connected to the solenoid 16. Further, a thermal head 17 is provided on the downstream side of the feed roller 11.
And a platen 18 are provided. In addition, printing ribbon
A supply shaft 20 around which both ends of 19 are wound and a winding shaft 21 are provided. Further, a discharging feed roller 22 and a pinch roller 23 are provided on the downstream side of the thermal head 18.
The feed rollers 11 and 22 and the platen 18 are driven by a motor 24. Details of the power transmission path between the motor 24 and the platen 18 will be described below. To do.

As shown in FIGS. 5 and 6, the frames 2 facing each other
5, 26 support shafts 27, 28 are erected, and one support shaft 27 rotatably holds a pair of left and right movable bodies 29.
Both ends of the platen 18 are rotatably held on both outer sides of 29. The motor 24 is held on a frame 25,
A belt 32 is wound around a pulley 30 that is directly connected to a pulley 31 and a pulley 31 that is a transmission wheel body that is fixed to the end of the support shaft 27, and further, a pulley 33 and a pulley 31 that are fixed to the end of the platen 18.
A belt 34 is wound around. Further, a fulcrum 35 is provided at the center of the fulcrum 28, and an oscillating body 36 is rotatably held at the fulcrum 35 along the longitudinal direction of the platen 18. The ridges 37 are formed on both sides of the oscillating body 36 and inside the movable bodies 29 on the left and right.
Both ends of are fixed.

Then, as shown in FIG. 1 (b) and FIG. 3 (b),
A pressing lever 39 for pressing one end of a shaft 38 penetrating the left and right movable bodies 29 is rotatably attached to the frame 25 about a shaft 40 as a fulcrum, and presses a roller 41 supported by the pressing lever 39. A cam 43 having a pressing portion 42 on the outer circumference
It is rotatably held by. Further, a switch 39a for detecting the operation of the pressing lever 39 is attached to the frame 25. A rotating plate 47, which constitutes one part of a clutch 46 that transmits the rotation of the motor 45 to the cam 43, is rotatably fitted to the shaft 44.

Next, the structure of the clutch 46 is shown in FIG. 1 (a), FIG. 2, FIG. 3 (a), and FIG. First, the motor 45 is the frame
The pulley 48 and shaft fixed to 25 and directly connected to this motor 45
A belt 50 is wound around a pulley 49 that is rotatably fitted to the shaft 44. A ratchet wheel 51 that rotates integrally with the pulley 49 is rotatably fitted to the shaft 44, and an arc-shaped nail 53 having a projection 52 that engages with the teeth of the ratchet wheel 51 is inwardly formed by the spring 54. It is biased and is rotatably held by the rotary plate 47 by the shaft 55. In addition, shafts 56, 57 and 58 are erected on the frame 25,
56 is a lever that is biased counterclockwise by a twist spring 59.
60 is rotatably held, and a shaft 57 is rotatably held by a lever 62 which is urged clockwise by a torsion spring 61.
A lever 64, which is urged clockwise by a spring 63, is rotatably held at 58. Furthermore, both ends are levers 62 and 64.
The center portion of the link 65 connected to is connected to one end of the lever 60, and the other end of the lever 60 is connected to the plunger 67 of the solenoid 66 fixed to the frame 25.

In such a structure, first, an outline of the operation will be described with reference to FIG. The card 68 having the magnetic stripe is inserted into the magnetic recording unit 1, and in the process of being conveyed by the conveying units 5, 6 and 7, predetermined data is recorded by the magnetic head 8 and the recorded contents are recorded by the magnetic head 9. Read. The bill 68 sent from the magnetic recording unit 1 is sent by the feed roller 11 and the pinch roller 14 and further sent by the platen 18 together with the print ribbon 19 while desired data is printed by the thermal head 17. Further, it is discharged by the feed roller 22 and the pinch roller 23.

Next, the contact / separation operation of the platen 18 with respect to the thermal head 17 will be described. In FIG. 1A, the lever 62 abuts against the clutch lever 53 to prevent the ratchet wheel 51 from engaging with the clutch 46.
1B is a side view showing a state in which the cam 43 is cut off, the cam 43 presses the roller 41 by the pressing portion 42, and the pressing lever 39 moves the shaft 40.
To rotate the movable body 29 counterclockwise about the support shaft 27 as a fulcrum against the force of the spring 37, thereby separating the platen 18 from the thermal head 17. It is a side view which shows the opened state. At this time, since the switch 39a switches the contact by the operation of the pressing lever 39, the state where the platen 18 is separated from the thermal head 17 is detected. In this state, the ticket 68 is simply conveyed, and the platen 18
Is driven by the driving force of the motor 24, but the thermal head 17
Since it does not receive the resistance of the
Can also be sent at high speed. At this time, the print ribbon 19 does not come into contact with the platen 18, so that the print ribbon 19 is not wastefully sent and is economical. The printing ribbon 19 is also replaced in this state with the platen 18 separated from the thermal head 17.

Next, when receiving the print command, the motor 45 first rotates,
The rotation is transmitted to the pulley 49 and the ratchet wheel 51 via the belt 50. At this time, since the clutch 46 is cut off, the load applied to the motor 45 is extremely small. Immediately after the motor 45 is started, the solenoid 66 is excited, the plunger 67 is attracted, the lever 60 rotates clockwise as shown in FIG. 2, and the link 65 slides downward to move the levers 62 and 64. The rotary plate 47 is separated from the outer circumference. At this moment, clutch lever 53 springs 54
Force causes the shaft 55 to pivot inwardly to engage the projection 52 with the teeth of the ratchet wheel 51. As a result, the rotary plate 47, the cam 43, the clutch lever 53, the ratchet wheel 51, and the pulley 49 integrally rotate counterclockwise. Immediately after this, the energization of the solenoid 66 is cut off, and the levers 60, 62, 64 are restored by the force of the torsion springs 59, 61, 63. Therefore, as shown in FIG. 3 (a), the lever 64 abuts against the tip of the clutch lever 53 and opposes the force of the spring 54 to rotate the clutch lever 53 in the outer peripheral direction to move it with the ratchet wheel 51. Disengage. That is, the clutch 46 is cut off. During this time, the cam 43 rotates 90 degrees, the hypert part, that is, the pressing portion 42 is disengaged from the roller 41, and the pressing lever 39 is rotated clockwise about the shaft 40 by the restoring force of the spring 37, so that the platen 18 is thermally released. Contact head 17 elastically. Immediately after this clutch 46 is cut off, the motor 45
Is stopped. Of course, the motor 45 may be connected and rotated. The platen 18 thermally prints the print ribbon 19
When a ticket 68 is sent while being pressed against 17, the ticket 68
Is sent by the platen 18 together with the print ribbon 19 and printed by the thermal head 17.

Again, in order to separate the platen 18 from the thermal head 17, the motor 45 is driven from the state shown in FIGS.
Of the lever by the same operation as the switching operation in the power transmission direction of
64 is retracted from the clutch lever 53, the ratchet wheel 51, the disc 47, the clutch lever 53, and the cam 43 are rotated, and immediately after that, the power supply to the solenoid 66 is cut off. As a result, the cam 43
After rotating 270 degrees, the lever 62 contacts the clutch lever 53 to cut the clutch 46. During this time, the cam 43 pushes the roller 41 and rotates the pressing lever 39 clockwise. This allows
The movable body 29 rotates counterclockwise to separate the platen 18 from the thermal head 17.

As described above, since the motor 45 is used as the drive source for the contact / separation operation of the platen 18 with respect to the thermal head 17, the operation is performed quietly. The force for rotating the lever 60 to connect and disconnect the clutch 46 is small, and the capacity of the solenoid 66 is small, so that the operation sound is small and the power consumption is small. Also,
A load is applied to the motor 45 when the platen 18 is separated from the thermal head 17, but the load gradually increases due to the rotation of the cam 43. In particular, since the cam 43 separates the platen 18 from the thermal head 17 within a rotation range of 270 degrees during one rotation, the load can be increased extremely gently. Therefore, the capacity of the motor 45 can be reduced, and since the cam 43 can be maintained at a desired position stopped by the operation of the clutch 46, the motor 45 is rotated only while the clutch 46 is operated. The power consumption can be further reduced.

Further, as shown in FIG. 5 and FIG. 6, a rocking body 36 that rocks along the longitudinal direction of the platen 18 around a fulcrum 35 that is disposed opposite to the central portion of the platen 18 is provided. By fixing both ends of the pair of left and right movable members 29 for biasing the pair of left and right movable members 29 holding both ends to the thermal head 17 to the both sides of the rocking member 36 and the movable member 29,
By rotating the rocking body 36, the strength of the left and right springs 37 can be balanced, and the pressure contact force of the left and right ends of the platen 18 with respect to the thermal head 17 can be made equal.
68 can be sent straight.

EFFECTS OF THE INVENTION As described above, according to the present invention, the platen can be operated quietly by using the motor as the drive source for the contact and separation of the platen with respect to the thermal head, and when the platen is separated from the thermal head, the motor is loaded. However, this load can be gently increased by the rotation of the cam, and therefore the capacity of the motor can be reduced, and the cam can be stopped at the desired position by the operation of the clutch. Since it can be maintained, it is possible to rotate the motor only while operating the clutch, which can further reduce power consumption, and further,
An oscillating body that oscillates along the longitudinal direction of the platen about a fulcrum arranged opposite to the center of the platen is provided.
Rotation of the oscillating body by fixing the both ends of the pair of left and right springs that urge the pair of left and right independent movable bodies holding both ends of the platen to the thermal head side to the both sides of the oscillating body and the movable body, respectively. By the action, the strength of the left and right ribs can be balanced, and the pressure contact force at the left and right ends of the platen with respect to the thermal head can be made equal, which has the effect that the recording paper can be fed straight.

[Brief description of drawings]

The drawing shows an embodiment of the present invention, and is shown in FIG.
Is a side view showing the power cut-off state of the clutch when the platen is separated from the thermal head, and FIG. 1 (b) is a side view showing the platen separated from the thermal head.
FIG. 2 is a side view showing the power transmission state of the clutch, FIG. 3 (a) is a side view showing the power cut-off state of the clutch when the platen is brought into contact with the thermal head, and FIG. 3 (b) is the platen. FIG. 4 is a side view showing a state in which the thermal head is contacted, FIG. 4 is a plan view showing a connecting structure of a motor, a clutch and a cam, and FIG. 5 is a side view showing a supporting structure of a movable body and a connecting structure of a motor and a platen. Figure, Figure 6 is the plan view,
FIG. 7 is a side view showing the entire structure in a reduced scale. 17 ... Thermal head, 18 ... Platen, 24 ... Platen driving motor, 29 ... Movable body, 31 ... Pulley (transmission wheel), 35 ... Support point, 36 ... Oscillating body, 37 ... Spring, 42 ...
… Pressing part, 43 …… Cam, 45 …… Cam drive motor, 46
...... Clutch

Claims (1)

[Claims] 1. A pair of left and right movable bodies, which are rotatably held at both ends of the platen, are rotatably provided, respectively, and a longitudinal direction of the platen is centered on a fulcrum arranged opposite to the center of the platen. An oscillating body which oscillates along the ridge is provided, and both ends of a pair of left and right springs for urging the movable body toward the thermal head are fixedly attached to both sides of the oscillating body and the movable body, respectively. A line thermal printer characterized in that a cam having a pressing portion for separating the body from the thermal head is rotatably provided, and the cam is connected to a motor via a clutch.