JPH0615904A - Image output device of thermal transfer type - Google Patents

Abstract

PURPOSE:To wind and rewind an ink sheet by means of a single motor. CONSTITUTION:A driving force from a motor 9 is transmitted to a a take-up roll 4 via a first one-way pulley 16 and a first torque-limiter 30. The title device is provided with a means which does not apply loads during rotation in the take-up direction and applies a load by a second torque limiter 24 during reverse rotation. A driving force from the motor 9 is transmitted to a supply roll 5 via a second one-way pulley 15 and a third torque-limiter 35. The device is further provided with a means for inhibiting an idling torque produced in the reverse rotation of the second one-way pulley 15 from being applied to the third torque limiter 35. The determined values, in order of magnitude, are for the first, third, and second torque limiters. The number of rotations of the first one-way pulley 16 which is idling is set greater than the number of rotations of the take-up roll 4 which is reversely rotating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer type image output apparatus including a thermal head and a platen such as a copying machine, a facsimile, a printer, a hard copy, and more particularly to driving an ink sheet supply roll and a take-up roll. The present invention relates to a thermal transfer type image output device having an ink sheet winding mechanism that can be driven by two motors.

[0002]

2. Description of the Related Art A conventional thermal printer mechanism will be described with reference to the drawings. FIG. 3 is a perspective view showing the structure of a conventional thermal printer. In this figure, reference numeral 1 indicates a thermal head, and a platen 2 is axially supported at a position facing the heating resistor of the thermal head 1, and an ink sheet 10 and an image receiving paper 3 are sandwiched between the thermal head 1 and the platen 2 and shown in FIG. Do not press the thermal head 1
The pressing force is applied from the back surface of the ink head 10 to bring the thermal head 1 into close contact with the ink sheet 10, the image receiving paper 3, and the platen 2, and the ink sheet 10 is wound while supplying electric power corresponding to the image data to the respective heating resistors. Meanwhile, a two-dimensional image is formed on the image receiving paper 3 by rotating the platen 2 in the direction A in the drawing.

The ink sheet 10 is unwound from a supply roll 5, and is wound up by a take-up roll 4 via guide rollers 21 and 22.
Wound up by. At this time, a torque limiter 6 is inserted between the supply roll 5 and the main body frame 7 in order to stabilize the conveyance of the ink sheet and prevent wrinkles generated during printing, and the take-up roll 4 uses the torque limiter 6. 8
The ink sheet is wound by the winding motor 9 via the, and an appropriate tension is applied to the ink sheet on both the supply side and the winding side.

By the way, the ink sheet 10 is always consumed by a certain length regardless of the printing rate of the transferred image, which is an obstacle to the reduction of running cost. Therefore, recently, a multi-time ribbon that can be used many times is being developed. In this case, the ink sheet used once needs to be rewound for reuse.

As one of the countermeasures, for example, Japanese Patent Publication No. 3
No. 39836 discloses a supply roll 5 and a take-up roll 4 each having a one-way clutch 1 as shown in FIG.
A mechanism is disclosed in which the driving force is transmitted to either one of the supply roll 5 and the take-up roll 4 depending on the rotation direction of the motor 9, the mechanism being connected to the motor 9 via 5 and 16.

This method will be briefly described.
Rotates in the direction of arrow a, the ink sheet 10 and the roll-shaped recording material 3 are conveyed forward, and a predetermined recording image is recorded on the roll-shaped recording material 3 by the heating resistor of the thermal head 1. At the same time, the motor 9 also rotates in the direction of arrow b,
The driving force is transmitted to the take-up roll 4 via the one-way clutch 16, and the ink sheet 10 is taken up by rotating the roll 4 in the direction of arrow c. At this time, the take-up speed transmitted to the take-up roll 4 is higher than the conveying speed of the ink sheet 10 by the platen 2, so that the torque limiter coaxially inserted in the take-up roll 4 causes slippage, and the slippage causes the ink. Front tension is applied to the seat 10.

When the motor 9 rotates in the direction of the arrow b as described above, the supply roll 5 does not rotate because the driving force is blocked by the one-way clutch 15, and when the ink sheet 10 is supplied in this state, the supply roll 5 Back tension is applied to the ink sheet 10 because a slip occurs in the torque limiter that is coaxially inserted in the ink sheet 10. Therefore, the ink sheet 10 does not have a slack as a whole.

Next, the motor 4 is used to rewind the ink sheet.
1 reversely rotates in the -a direction, and at the same time, the motor 9 reversely rotates in the -b direction. Contrary to the case where the motor 9 rotates in the b direction, the driving force to the winding roll 4 is interrupted by the one-way clutch 16 and supplied. One-way clutch 1 for roll 5
The roll-shaped recording material 3 which is also rewound by being transmitted through the roll 5 to rotate in the direction of arrow d.
It is wound at the same speed as. At this time, similarly to when the motor 9 rotates in the b direction, back tension and front tension are applied to the ink sheet 10 due to the sliding of the respective torque limiters, so that the ink sheet 10 does not sag.

[0009]

However, the ink sheet winding mechanism of this system has the following problems. When printing, set the torque limiter so that the front tension is high and the back tension is low.
If you simply reverse and rewind in this state, the front tension will be smaller than the back tension this time,
Actually, it is not possible to rewind stably.

Even if the one-way clutch idles, some idling torque is transmitted to the shaft, the power is also transmitted to the rolls that originally do not need to transmit the driving torque, and the direction thereof is opposite to the direction in which the ink sheet is wound. As a result, the roll reverses and the ink sheet sags.

At the time of rewinding, there is a slip due to the torque limiter between the drive motor and the supply roll, so the winding efficiency is not good and high-speed winding is difficult. Therefore, the present invention has been made in view of the above points, and enables winding and rewinding with one motor, and further, without using an actuator other than the motor, the winding and rewinding can be performed. In either case, it is an object of the present invention to provide a thermal transfer type image output device having an ink sheet transport mechanism that enables reliable transport of an ink sheet and can rewind at high speed during rewinding.

[0012]

In order to solve the above problems, according to the present invention, as a first structure, a drive force transmission mechanism for a winding roll uses a drive force from a motor as a first one way. A mechanism for inputting the output of the first torque limiter to the take-up roll via a clutch and transmitting the output of the first torque limiter to the take-up roll, and no load is applied when the take-up roll rotates in the take-up direction. Without taking
A means for applying a load torque by a second torque limiter to the winding roll when reversing is provided, and the driving force transmission mechanism to the supply roll is configured so that the driving force from the motor is passed through the second one-way clutch to the third side. Of the third torque limiter to transmit the output of the third torque limiter to the supply roll, and the idling torque when the second one-way clutch is reversed is applied to the third torque limiter. Rewinding the ink sheet by providing a means for prohibiting the setting, and setting the set values of the first to third torque limiters in descending order to the first torque limiter, the third torque limiter, and the second torque limiter. At this time, the rotation speed NP of the first one-way clutch when the first one-way clutch idles is determined by the rewound ink sheet. It was set to be greater than the rotational speed NR of the take-up roll to rotate together I.

Further, as a second structure, a portion corresponding to the driving force transmission mechanism to the supply roll in the first configuration is a mechanism for transmitting the driving force from the motor to the supply roll via the second one-way clutch. Further, means for applying a slip torque by a third torque limiter is independently provided to the supply roll, and the set values of the first to third torque limiters are set in descending order of the set values of the first torque limiter and the third torque limiter. Torque limiter and second torque limiter, the rotational speed NP2 of the second one-way clutch when the second one-way clutch idles when the ink sheet is wound, is rotated by the wound ink sheet. When the ink sheet is rewound, the first one-way clutch is set to be higher than the rotation speed NR2 of the supply roll. Rotation speed NP1 of the first one-way clutch at the time of rolling is set to be larger than the rotational speed of the winding roll NR1 to rotate together by winding the ink sheet to be returned.

[0014]

In the first structure, the front tension and the back tension are respectively controlled by the first and third torque limiters at the time of winding, and the third and the second tensions at the time of rewinding.
The torque limiter allows stable and reliable ink sheet transport while applying front tension and back tension.

Further, even if the first and second one-way clutches run idle, the rotation of the rotary shaft due to the idling torque is not possible, so that the ink sheet is prevented from being loosened. In the second configuration, the front and back tensions are respectively applied by the first and third torque limiters during winding, and the tension is stable while the tension is applied by the second torque limiter during rewinding. Therefore, it is possible to reliably convey the ink sheet.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a top view of an embodiment of the first structure according to the present invention, and particularly the drive system is partially shown in section.
In this figure, the thermal head 1 is an ink sheet 10
The image receiving paper 3 and the ink sheet 10 are illustrated while sandwiching the image receiving paper 3 together with the platen 2 and pressing it from the front side to the back side of the drawing to supply electric power corresponding to the image data to each heating resistor of the thermal head. Images are transferred while being conveyed in the printing direction. By sliding both the supply roll 5 and the take-up roll 4 downward in the drawing, the coupling with the reel portions 25 and 26 can be released, and the used ink sheet can be easily replaced.

First, the winding drive system will be described. The power from the drive pulley 11 directly connected to the motor 9 is the belt 13.
Is transmitted to the one-way pulley 16 via. This pulley has a built-in one-way clutch that transmits the torque to the shaft 40 in the -c direction but does not transmit the torque in the c direction. Further, the shaft 40 has an inner cylinder 27 and a sliding plate 2
8. A torque limiter 30 including an outer cylinder 29 is attached, and the reel portion 25 is integrally formed with the outer cylinder 29. The torque limiter 30 is configured such that the inner cylinder 27 and the shaft 40 are prevented from rotating by a spring pin or the like, and both rotate integrally.

When the torque applied to the drive shaft 40 exceeds the torque set by the torque limiter 30, slip occurs on the sliding plate 28 and the slip torque is transmitted to the reel section 25. Further, a gear 36 is formed around the outer cylinder 29, and the gear 36 meshes with an axial one-way gear 17 provided in parallel with the shaft 40. This one-way gear has a built-in one-way clutch so that it locks when it rotates in the -d direction. Further, a torque limiter 24 is attached coaxially with the one-way gear 17, and the outer cylinder of the torque limiter 24 is the main body frame 7
The rotation is stopped by a claw extending from.

Next, the rewinding drive system will be described. The driving force from the motor 9 is transmitted to the one-way pulley 15 via the drive pulley 11 and the belt 12. The one-way pulley 15 has a built-in one-way clutch so that the driving force is transmitted to the shaft 31 when rotated in the b direction, but the driving force is not transmitted when rotated in the -b direction. The inner cylinder 32 and the sliding plate 3 are provided on the supply roll 5 side of the shaft 31.
3, a torque limiter 35 composed of an outer cylinder 34 is coaxially attached, and the inner cylinder 32 is rotated integrally with the shaft 31 by means of a spring pin or the like to prevent rotation of the shaft 31 and applied to the shaft 31. When the torque exceeds the set value of the torque limiter 35, the sliding plate 33 slips and the slip torque is transmitted to the outer cylinder 34.

The outer cylinder 34 is integrally formed with a reel portion 26 for meshing with a concave meshing portion at the end of the supply roll 5 and transmitting power. Furthermore, the shaft 31
One-way clutch 14 is attached to the other end of
A rotation stopper on the outer cylinder of the one-way clutch 14 is locked to the main body frame 7. The purpose of the one-way clutch 14 is to allow the shaft 31 to rotate only in the b direction and to prohibit the rotation in the -b direction. Next, the operation will be described.

First, at the time of printing, the image receiving paper 3 is set, the thermal head 1 is pressed in the platen direction, and the platen 2
The image is transferred while rotating the motor 9 in the -a direction while rotating the motor 9 in the e direction. At this time, when the driving force from the motor 9 is transmitted to the one-way pulley 16 via the belt 13, the one-way pulley 16 directly transmits the driving force to the shaft 40 by the action of the built-in one-way clutch. Then, the set value of the torque limiter 30 is determined so that a tension smaller than the frictional force (leftward direction) applied to the image receiving paper 3 and the ink sheet 10 at the sandwiching portion between the thermal head 1 and the platen 2 is applied to the ink sheet. That is, in the above-described state, the torque limiter 30 always causes slippage, and the set torque is applied to the winding roll 4. At the same time, the one-way gear 17 meshing with the gear 36 formed around the outer cylinder 29 rotates in the d direction, but since the built-in one-way clutch is in the idling direction, the torque limiter 24 has no influence on the winding operation. .

In the supply roll 5, the driving force is transmitted to the one-way pulley 15 via the belt 12, and the one-way pulley 15 rotates in the -b direction, but the shaft 31
No drive force is transmitted to the shaft 31. Further, since the shaft 31 is restrained from rotating in the −b direction by the action of the one-way clutch 14, the shaft 31 is restrained from rotating completely. Therefore, when the ink sheet is conveyed in the printing direction along with the printing and the pulling force in the −b direction acts on the supply roll 5, the torque limiter 35 slips, and the supply roll 5 has a torque determined by the set value of the torque limiter 35. Will be applied.

That is, as described above, at the time of printing, the tension determined by the torque limiter 35 between the supply roll 5 and the thermal head 1 and the torque between the thermal head 1 and the take-up roll 4 are increased. The tension determined by the limiter 30 is applied.
Here, for example, the set value of the torque limiter 35 is 0.5 kg.
f · cm, set value of torque limiter 30 is 1 kgf · c
m, the diameter of the winding roll 4 is 20 mm, and the supply roll 5 is
If the diameter is 18 mm, the front tension is 1 kg.
f and back tension of 0.56 kgf can be maintained.

Next, when rewinding, the driving force is applied to the supply roll 5 side. To explain the mechanism, first, the supply roll 5 side rotates the motor 9 in the direction a. The driving force is applied to the one-way pulley 15 via the belt 12. This one way pulley 1
Since the driving force of No. 5 is transmitted to the shaft 31 when rotating in the b direction, the set torque determined by the torque limiter 35 is transmitted to the supply roll 5. At this time, the one-way clutch 14 attached to the other end of the shaft 31 always functions as an overrunning clutch and does not restrain the rotation of the shaft 31 in the b direction.
Has no effect on the rotation of the shaft 31.

On the take-up roll 4 side, the rotation of the motor 9 in the direction a is transmitted to the one-way pulley 16. However, the built-in one-way clutch acts as an overrunning clutch, and the driving force thereof is the shaft 40. Is not transmitted to. A rewinding torque in the c direction is applied to the take-up roll 4 by the action of the ink sheet 10 that is rewound on the supply roll 5, but the one-way gear 1 from the take-up roll 4 via the reel unit 25 to the one-way gear 1
The rotational torque in the anti-d direction is transmitted to 7, and the back tension determined by the torque limiter 24 is applied.

At this time, in order for the one-way pulley 16 to always act as an overrunning clutch, the rotation speed NP of the one-way pulley 16 in the c direction is
It is necessary that the rotational speed NR in the c direction of the take-up roll 4 that rotates when the ink sheet 10 is rewound is higher than the rotational speed NR. For that purpose, for example, the diameter of the winding roll 4 is 20 m.
m, the diameter of the supply roll 5 is 18 mm, and the ratio of the diameters of the one-way pulleys 15 and 16 is 3: 2, when the motor 9 is rotated in the direction a, the rotation speed NP of the one-way pulley 16 is The rotational speed NR of 4 is about 1.7 times, and the one-way pulley 16 acts as an overrunning clutch.

Further, when 0.2 kgf · cm is adopted as the set value of the torque limiter 24, the front tension of 0.56 kgf and the back tension of 0.2 kgf are maintained, and at the time of rewinding, the torque limiter 35 and the torque limiter 24. Ink sheet 1 with tension determined by
0 will be transported.

In this embodiment, the one-way pulley 1
Although the ratio of the diameters of 5 and 16 is 3: 2, the ratio is not limited to this value. FIG. 2 is a top view of an embodiment of the second structure according to the present invention, and the portions common to FIG. 1 and the portions having the same functions are designated by the same reference numerals as those in FIG.

In FIG. 2, the thermal head 1 sandwiches the ink sheet 10 and the image receiving paper 3 together with the platen 2 and presses them from the front side to the back side of the drawing, and applies heat corresponding to image data to each heating resistor of the thermal head. While supplying, the platen 2 in the e direction and the winding roll 4 in -c
The image transfer is performed while rotating the image receiving paper 3 and the ink sheet 10 in the printing direction as shown in the drawing. The take-up roll 4 and the supply roll 5 are both slidable downward in the drawing so that the reel portions 25, 2 provided on the drive side.
The connection with 6 can be released, and the used ink sheet can be easily replaced.

First, the winding drive system on the right side will be described.
The power from the drive pulley 11 directly connected to the motor 9 is transmitted to the one-way pulley 16 via the belt 13.
The one-way pulley 16 has a built-in one-way clutch so that the torque is transmitted to the shaft 40 in the −c direction, but the torque is applied to the shaft 40 in the c direction so as not to transmit the applied torque. Further, a torque limiter 30 including an inner cylinder 27, a sliding plate 28, and an outer cylinder 29 is attached to the shaft 40, and the reel portion 25 is integrally formed with the outer cylinder 29. The torque limiter 30 is configured such that the inner cylinder 27 and the shaft 40 are prevented from rotating by a spring pin or the like, and both rotate integrally. When the torque applied to the drive shaft 40 exceeds the torque set by the torque limiter 30, the sliding plate 28 slips and a relative rotational speed difference occurs between the inner cylinder 27 and the outer cylinder 29. This slip torque is transmitted to the reel unit 25.

Further, a gear 36 is formed around the outer cylinder 29, and the gear 36 meshes with a one-way gear 17 on another shaft provided in parallel with the shaft 40. The one-way gear 17 has a built-in one-way clutch so as to be locked when rotated in the -d direction.

Further, a torque limiter 24 is attached coaxially with the one-way gear 17, and the outer cylinder of the torque limiter 24 is prevented from rotating by a claw extending from the main body frame 7. Therefore, the transmission torque when the one-way gear 17 is rotating in the lock direction has a value determined by the torque limiter 24.

Next, the rewinding drive system on the left side will be described. The driving force from the motor 9 is transmitted to the one-way pulley 15 via the drive pulley 11 and the belt 12. When this one-way pulley 15 is rotated in the b direction, the shaft 3
1 has a built-in one-way clutch so that the driving force is transmitted, but the driving force is not transmitted when rotated in the -b direction. On the supply roll 5 side of the shaft 31, a reel portion 26 for engaging with a concave meshing portion of the end portion of the supply roll 5 and transmitting power is attached so as to be rotatable integrally with the shaft 31. On the other hand, the other end of the shaft 31 is fixed to the inner cylinder of the torque limiter 51, and the outer cylinder of the torque limiter 51 is attached to the main body frame 7 by a set screw 52. Therefore, the slip torque determined by the torque limiter 51 is always applied to the shaft 31.

Next, the operation will be described. First, at the time of printing, the image receiving paper 3 is set, the thermal head 1 is pressed in the platen direction with a predetermined pressure, and the image is transferred while rotating the platen 2 in the e direction and the motor 9 in the -a direction. To do. At this time, when the driving force from the motor 9 is transmitted to the one-way pulley 16 via the belt 13, the one-way pulley 16 directly transmits the driving force to the shaft 40 by the action of the built-in one-way clutch. Then, the torque limiter 3 is applied so that a tension smaller than the frictional force (leftward direction) applied to the image receiving paper 3 and the ink sheet 10 at the sandwiching portion between the thermal head 1 and the platen 2 is applied to the ink sheet.
If the set value of 0 is determined, the torque limiter 30 always causes slip in the above-described printing state, and the take-up roll 4
The torque set by the torque limiter 30 is applied to. At the same time, the one-way gear 17, which meshes with the gear 36 formed around the outer cylinder 29, rotates in the d direction,
Since the built-in one-way clutch is in the idling direction, the torque limiter 24 has no influence on the winding operation and does not contribute to the torque of the winding roll 4.

On the other hand, the supply roll 5 rotates in the direction for feeding out the ink sheet, but the driving force is transmitted to the one-way pulley 15 via the belt 12 and the one-way pulley 15 rotates in the -b direction. No driving force is transmitted to the shaft 31. Therefore, when the ink sheet is conveyed in the printing direction along with printing and a pulling force in the −b direction acts on the supply roll 5, the torque limiter 5
1 causes slippage, and the supply roll 5 has a torque limiter 5
The torque determined by the set value of 1 is applied.

That is, as described above, at the time of printing, the front tension determined by the torque limiter 30 between the thermal head 1 and the winding roll 4,
Further, back tension determined by the torque limiter 51 is applied between the supply roll 5 and the thermal head 1. Here, for example, the set value of the torque limiter 51 is 0.5 kgf · cm, the set value of the torque limiter 30 is 1 kgf · cm, and the diameter of the winding roll 4 is 20 m.
m, and the diameter of the supply roll 5 is 18 mm, the front tension of 1 kgf and the back tension of 0.56 kgf can be maintained. At this time, in order for the one-way pulley 15 to always act as an overrunning clutch, the one-way pulley 15-
It is necessary that the rotation speed NP in the b direction is higher than the rotation speed NR in the −b direction of the supply roll 5 that is rotated by winding the ink sheet 10. For that purpose, for example, the diameter of the winding roll 4 is 20 mm and the diameter of the supply roll 5 is 18 m.
m and the diameter of the one-way pulleys 15 and 16 is 2.5:
If it is set to 2, when the motor 9 is rotated in the −a direction, the rotation speed NP of the one-way pulley 15 is equal to the torque limiter 3
Assuming that the slip at 0 is 35%, the supply roll 5
Therefore, the one-way pulley 15 always acts as an overrunning clutch.

Next, when the ink sheet is rewound, the thermal head 1 is usually retracted, and the ink sheet is rewound with a certain gap between the thermal head 1 and the platen 2. When the motor 9 is rotated in the a direction, the driving force is applied to the one-way pulley 15 via the belt 12.

When the one-way pulley 15 rotates in the b direction, its driving force is transmitted to the shaft 31, so that the transmitted power from the motor 9 is directly transmitted. Next, with respect to the take-up roll 4 side at this time, the rotation of the motor 9 in the a direction is transmitted to the one-way pulley 16. However, the built-in one-way clutch acts as an overrunning clutch, so that the driving force thereof is the shaft 40. Is not transmitted to. A rewinding torque in the c direction is applied to the take-up roll 4 by the action of the ink sheet 10 that is rewound on the supply roll 5, but from the take-up roll 4 to the one-way gear 17 via the reel unit 25 to the gear unit 36. -D
The rotation in the direction is transmitted, and the tension determined by the torque limiter 24 is applied to the ink sheet 10.

At this time, in order for the one-way pulley 16 to always act as an overrunning clutch, the rotational speed NP of the one-way pulley 16 in the c direction is
It is necessary that the rotational speed NR in the c direction of the take-up roll 4 that rotates when the ink sheet 10 is rewound is higher than the rotational speed NR. For that purpose, just as in the case described above, if the diameter of the winding roll 4 is 20 mm, the diameter of the supply roll 5 is 18 mm, and the diameters of the one-way pulleys 15 and 16 are 2.5: 2, the motor is When 9 is rotated in the a direction, the rotational speed NP of the one-way pulley 16 becomes about 1.4 times the rotational speed NR of the take-up roll 4, and the one-way pulley 16 always acts as an overrunning clutch. Further, when 0.2 kgf · cm is adopted as the set value of the torque limiter 24, the tension of 0.2 kgf is maintained and the torque limiter 2 is used during rewinding.
The ink sheet 10 is transported with a tension determined by 4.

In the case of printing, since the driving force from the motor 9 is transmitted to the take-up roll through the torque limiter 30, there is slippage in the torque limiter 30, but it is supplied from the motor 9 during rewinding. Since there is no slipping element up to the roll 5, rewinding power is directly transmitted and high speed rewinding is possible.

In this embodiment, the one-way pulley 1
The diameters of 5 and 16 are 2.5: 2, but the diameter is not limited to this value, and it is sufficient that the one-way pulley 15 and the one-way pulley 16 can act as an overrunning clutch. In the embodiments of the first and second configurations, the belt is used as the power transmission means from the motor, but other transmission means such as a method using a gear train may be used. Further, although the friction type is shown as the torque limiter, it is not limited to that type and, for example, a powder type torque limiter may be used.

[0042]

As described above, according to the present invention,
As a first configuration, the drive force transmission mechanism to the winding roll inputs the drive force from the motor to the first torque limiter via the first one-way clutch, and outputs the output of the first torque limiter. With a mechanism to transmit to the take-up roll,
Further, when the take-up roll rotates in the take-up direction, no load is applied, and when the take-up roll rotates in the reverse direction, a means for applying a load torque to the take-up roll by the second torque limiter is provided, and a drive force transmission mechanism to the supply roll is provided. As a mechanism for inputting the driving force from the motor to the third torque limiter via the second one-way clutch and transmitting the output of the third torque limiter to the supply roll, and further for reversing the second one-way clutch. A means for prohibiting the input shaft to the third torque limiter from rotating due to the idling torque when the first torque limiter is set to the first torque limiter is set in descending order of the set values of the first to third torque limiters. The third torque limiter and the second torque limiter are used. When the ink sheet is rewound, the first one-way clutch idles. Since the rotation speed of the latch is set to be higher than the rotation speed of the take-up roll that rotates with the ink sheet being rewound, an actuator for switching the torque limiter between winding and rewinding is required. Instead, the driving force is transmitted to either the supply roll or the take-up roll depending on the rotation direction of the motor, and the supply roll is synchronized with the conversion of the rotation direction of the motor during winding and rewinding of the ink sheet. It is possible to automatically switch the proper tension between the winding roll and the take-up roll to convey the ink sheet, thus ensuring a good image during printing, and a reliable ink sheet with less meandering. It is possible to wind up.

According to the second structure of the present invention, the driving force transmission mechanism to the winding roll is the same as that of the first structure, but the driving force transmission mechanism to the supply roll is from the motor. A mechanism for transmitting the driving force to the supply roll via the second one-way clutch, and means for applying a slip torque by a third torque limiter to the supply roll are independently provided, and the first to third torques are provided. The first torque limiter, the third torque limiter, and the second torque limiter are set in descending order of the set values of the limiters, and the second one-way clutch when the second one-way clutch idles when the ink sheet is wound. So that the number of rotations of the ink sheet is higher than the number of rotations of the supply roll that is rotated by the ink sheet to be wound, and when the ink sheet is rewound, the first one-way Since the rotation speed of the first one-way clutch when the clutch is idling is set to be higher than the rotation speed of the take-up roll that is rotated by the rewound ink sheet, the same effect as that of the first configuration can be obtained. Further, when rewinding, the motor and the supply roll are directly connected, so that rewinding can be performed at high speed.

[Brief description of drawings]

FIG. 1 is a top view showing an embodiment of a thermal transfer image output device according to the present invention.

FIG. 2 is a top view showing another embodiment of the thermal transfer type image output device according to the present invention.

FIG. 3 is a perspective view showing a configuration of a conventional thermal printer.

FIG. 4 is an explanatory diagram showing an embodiment of an ink sheet transport mechanism in a conventional thermal printer.

[Explanation of symbols]

 1 Thermal Head 2 Platen 3 Image Receiving Paper 4 Winding Roll 5 Supply Roll 9 Motor 10 Ink Sheet 12 Belt 13 Belt 15 One-way Pulley 16 One-way Pulley 17 One-way Gear 24 Torque Limiter 25 Reel Section 26 Reel Section 30 Torque Limiter 31 Shaft 35 Torque Limiter 40 axis 51 torque limiter

Claims (5)

[Claims] 1. A thermal transfer type image output device for transferring the ink of an ink sheet to an image receiving paper to transfer an image to the image receiving paper, wherein the ink of the ink sheet is transferred to the image receiving paper, A thermal head that acts on the ink sheet, a supply roll that winds the ink sheet, a take-up roll that winds the ink sheet supplied from the supply roll, and the take-up roll. A motor for applying a rotational torque to the roll and the supply roll is provided, and a drive force transmission mechanism to the winding roll is a first torque limiter for transmitting a drive force from the motor through a first one-way clutch. To a mechanism for transmitting the output of the first torque limiter to the take-up roll, and the take-up roll rotates in the take-up direction. There is provided no load at this time, and a means for applying a load torque by the second torque limiter to the winding roll at the time of reverse rotation is provided, and the driving force transmission mechanism to the supply roll is the driving force from the motor. Is input to the third torque limiter via the second one-way clutch, and the output of the third torque limiter is transmitted to the supply roll. Further, idling when the second one-way clutch is reversed. Means is provided for prohibiting rotation of the input shaft to the third torque limiter by torque, and the driving force is transmitted to either the supply roll or the take-up roll depending on the rotation direction of the motor, At the time of winding or rewinding the ink sheet, the tension of the ink sheet is constantly applied while applying tension between the supply roll and the winding roll. Thermal transfer type image output apparatus characterized by performing a transmission. 2. A thermal transfer type image output device for transferring the ink of an ink sheet to an image receiving paper to transfer an image to the image receiving paper, wherein the ink of the ink sheet is transferred to the image receiving paper, A thermal head that acts on the ink sheet, a supply roll that winds the ink sheet, a take-up roll that winds the ink sheet supplied from the supply roll, and the take-up roll. A motor for applying a rotational torque to the roll and the supply roll is provided, and a drive force transmission mechanism to the winding roll is a first torque limiter for transmitting a drive force from the motor through a first one-way clutch. To a mechanism for transmitting the output of the first torque limiter to the take-up roll, and the take-up roll rotates in the take-up direction. There is provided no load at this time, and a means for applying a load torque by the second torque limiter to the winding roll at the time of reverse rotation is provided, and the driving force transmission mechanism to the supply roll is the driving force from the motor. Is a mechanism for transmitting to the supply roll via a second one-way clutch, and further, means for applying a slip torque by a third torque limiter is independently provided to the supply roll, and depending on the rotation direction of the motor. The driving force is transmitted to either one of the supply roll or the take-up roll, and at the time of winding and rewinding of the ink sheet, the tension of the ink sheet is constantly applied while applying tension between the supply roll and the take-up roll. A thermal transfer type image output device characterized by carrying. 3. The first torque limiter, the third torque limiter, and the second torque limiter in descending order of the set values of the first to third torque limiters. Thermal transfer image output device. 4. The revolving speed of the first one-way clutch when the first one-way clutch idles when rewinding the ink sheet is more than the revolving speed of the take-up roll that is rotated by the rewound ink sheet. The thermal transfer image output device according to claim 1, wherein the thermal transfer image output device is set to be large. 5. When the driving force is transmitted to the take-up roll and the ink sheet is taken up, the number of revolutions of the second one-way clutch when the second one-way clutch idles is the ink that is taken up. So as to be higher than the rotation speed of the supply roll that rotates together with the sheet, and when the driving force is transmitted to the supply roll to rewind the ink sheet,
The rotation speed of the first one-way clutch when the first one-way clutch idles is set to be higher than the rotation speed of a take-up roll that is rotated by an ink sheet to be rewound. Thermal transfer image output device.