JPH05278285A - Thermal printer - Google Patents

Abstract

PURPOSE:To prevent an ink sheet from jamming by reducing a margin when an ink applicable pattern of the ink sheet of a thermal printer is designed. CONSTITUTION:A thermal printer is constructed as follow; an ink sheet winding roll 4 prevents a reversion with a ratchet mechanism 49, and restrains an once wound ink sheet 10 from being drawn out; further, a ratchet mechanism 43 and a regular turning preventive means which can control it from an outside wherein a solenoid 27 is used are provided to an ink sheet feed roll 5; the ink sheet 10 can be allowed or inhibitted to be drawn out from the ink sheet feed roll 5 by turning on or off the solenoid 27 from the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a facsimile, a word processor, a printer and the like, and more particularly to a thermal printer including a print head and a platen.

[0002]

2. Description of the Related Art The mechanism of a conventional thermal printer will be described with reference to the drawings. FIG. 2 is a perspective view showing the structure of a conventional thermal printer. In this figure, reference numeral 1
Denotes a thermal head, and a platen 2 is axially supported at a position facing the heating resistor of the thermal head 1, and the ink sheet 10 and the image receiving paper 3 are provided on the thermal head 1 and the platen 2.
And pressing force is applied from the back surface of the thermal head 1 by a pressing means (not shown) to bring the thermal head 1 into close contact with the ink sheet 10, the image receiving paper 3, and the platen 2.
While supplying the electric power corresponding to the image data to each heating resistor, while winding the ink sheet 10, the platen 2
2D image on the receiving paper 3 by rotating the
It is formed on top.

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 appropriate tension is applied to the ink sheet on both the supply side and the winding side.

Further, as shown in FIG. 3, the ink sheet 10 has a region 1 coated with a meltable or sublimable yellow ink (Y), magenta ink (M), and cyan ink (C).
1, 12 and 13 and clear area 14 with nothing applied
And the detection marks 15 to 17 are provided for each transparent region. The detection marks 15 to 17 are read by the transmission type detection mark sensor pair 18 in FIG.
It is used to find the head of each color ink sheet. The area in which the ink application area and the transparent area are combined has the same size L1 for each color, and a color image is obtained by superimposing three colors of yellow, magenta, and cyan on the same image receiving paper. Therefore, in order to output a color image on one image receiving sheet, the ink sheet is consumed by L3. By way of example, in the case of printing yellow, for example, what is used for printing is a region of width W and longitudinal direction T indicated by reference numeral 23 in FIG. 3, and a certain margin is provided around the printing region 23. ing. In particular, in the ink sheet conveyance direction, a margin area having a size of T1 and T2 is provided in order to provide a margin for a change in the feed amount, and both T1 and T2 are often set to be slightly larger.

Further, reference numeral 19 in FIG. 2 is a reflection type edge sensor 19 for detecting an edge of the image receiving paper 3, and determines a writing start point of the image receiving paper 3. Next, the operation of the conventional example will be described in order with reference to FIGS. 4 to 6, the guide roller 21 used in the conventional example is used.
A guide plate 21 is used instead of the above, but the operation is the same.

First, there is no guarantee that the ink sheet 10 is stretched, for example, immediately after the ink sheet is exchanged. As shown in FIG. 4A, the ink sheet 10 is slack and comes into contact with the platen 2. It is possible that If the image receiving paper is fed in this state, the ink sheet 10
May cause a jam. Therefore, as an initial operation, in order to remove the slack of the ink sheet 10, it is necessary to first perform the pinning operation, and subsequently perform the cueing of the yellow area of the ink sheet. Therefore, the take-up roll 4 is rotated in the direction A in FIG. 4A to wind up the ink sheet, and when the yellow detection mark 15 is detected by the detection mark sensor pair 18 as shown in FIG. The driving of the take-up motor 9 is stopped. At this time, supply roll 5
Rotates in the E direction in FIG. 4B in conjunction with the feeding of the ink sheet 10.

Next, as shown in FIG. 4 (c), the platen 2 is rotated in the normal direction (direction C in the figure) by a driving means (not shown) to feed the image receiving paper 3, and after the image receiving paper is fed out by a fixed amount. As shown in FIG. 4 (d), the thermal head 1 is brought close to the platen 2 until it is almost in a crimped state, and the conveyance direction of the image receiving paper 3 is guided by the thermal head 1 and guided in the direction of the platen 2 and the pinch roller 32. , The image receiving paper 3 is fed around the platen 2. At this time, the ink sheet 10 is fed out as the head descends. However, since the rotations of both the supply roll 5 and the take-up roll 4 are not restricted, the supply roll 5 moves to E as shown in FIG. In some cases, the ink sheet is rotated and fed out, and in another case, as shown in FIG. 5A, the take-up roll 4 is reversed and the once wound ink sheet is pulled back. Particularly in the latter case, the yellow detection mark 15 moves to the upstream side of the detection mark sensor pair 18 as shown in FIG.

Next, the edge of the image receiving paper 3 is detected and positioned by the edge sensor 19, but in order to remove the influence of the backlash of the paper feed drive system, the image receiving paper 3 is moved to the position shown in FIG. 5 (b). After passing the edge sensor 19 once, the image receiving paper 3 is pulled back until the edge sensor 19 is passed (as shown in FIG.
Rotation), and further, as shown in FIG. 5D, the platen 2
Is reversed in the C direction, and positioning is completed when the edge sensor 19 detects an edge.

Next, printing is performed. As shown in FIG. 6 (a), the thermal head 1 is moved toward the platen 2 and the ink sheet 10 and the image receiving paper 3 are pressure-bonded with each other at a prescribed pressure, so that the thermal head 1 While sending the pixel information to the platen 2, rotate the platen 2 in the direction C in FIG.
At the same time, the take-up roll 4 is normally rotated in the A direction, so that the Y component of a desired image can be formed on the image receiving paper 3.

When the printing of the Y component is completed, the data transfer to the thermal head 1, the normal rotation of the platen 2 and the driving of the ink sheet winding motor 9 are stopped, and the thermal head 1 is stopped.
To retreat. At this point, since the printing of the final line of the Y component has been completed, the ink sheet 10 and the image receiving paper 3 are in close contact with or in contact with each other (the state of FIG. 6B), and the platen 2 is rotated in the D direction in this state. Then, if the image receiving paper 3 is returned and the image receiving paper 3 is cueed, paper jam or jam of the ink sheet 10 will occur. Therefore, prior to the returning operation of the image receiving paper 3, the ink sheet is idly fed and rotated in the direction A as shown in FIG. 6C to pin the ink sheet 10, and at the same time, the magenta mark 16 Is detected (FIG. 6C).

The M component is printed by the same process as the Y component printing. Similarly, the C component is printed, the head retraction and the ink sheet pinning are performed, and the yellow mark 15 is detected and the platen 2 is rotated in the D direction in preparation for printing the next image. Then, the image receiving paper 3 is discharged, and a series of operations is completed.

Through the above process, a color image can be formed on the image receiving paper.

[0013]

However, the thermal printer having the above structure has the following problems. In the pin tensioning operation for removing the slack of the ink sheet, that is, in the process from FIG. 4A to FIG. 4B, the ink sheet take-up amount of the take-up roll 4 is set to drive the ink sheet take-up motor. Even if it is obtained from time management or the number of pulses by the encoder, the diameter of the take-up roll changes depending on the take-up amount of the ink sheet, so that the actual take-up amount cannot be accurately detected. Moreover, in the above configuration, since the supply roll 5 also rotates in conjunction with the winding of the ink sheet at the time of winding, it is possible to wind up more than the amount necessary for pinning and waste the ink sheet. There was a nature. On the contrary, the winding amount may be insufficient and the winding may not be completed completely. Therefore, conventionally, as shown in FIG. 3, margin portions T1 and T2 are provided in front of and behind the print area, and the margin portions T1 and T2 are secured in a considerably large amount. Therefore, the ratio of the area 23 actually used for printing in the ink application areas 11 to 13 is small, and the waste of the ink sheet tends to increase.

When the head is pressure-bonded to start printing after the head of the image receiving paper 3 and the mark detection of the ink sheet are completed, that is, FIG. 4 (c) to FIG. 4 (d) or FIG.
The ink sheet is fed out when shifting to (a),
It is not decided whether it is fed from the supply roll 5 as shown in FIG. 4D or is fed from the take-up roll 4 as shown in FIG. 5A. It depends on the balance of the ink sheet wound around the roll 5. For example, when the ink is fed from the winding side, the detected ink mark moves to the head side as shown in the figure, and the printing start points are not always the same for the Y, M, and C inks. On the contrary, since it may be fed from the supply roll, the margin T1 between the mark on the ink sheet 10 and the tip of the ink application area is conventionally used.
Was taken to correspond to these.

As shown in FIG. 4 (d), when the image receiving paper 3 is fed around the platen, the head is in a state close to pressure bonding because it guides the conveyance path of the image receiving paper 3. Moreover, FIG.
As shown in (b), (c), and (d), when the image receiving paper 3 is positioned at the printing start point, the platen is repeatedly rotated forward / reversely to prevent backlash of the paper feed drive system. Perform positioning. In this case, due to the action of static electricity that charges the ink sheet or the image receiving paper 3, the ink sheet is also fed out as the image receiving paper 3 is conveyed, and is conveyed together with the image receiving paper 3, for example, as shown in FIG. In this case, the supply roll 5 was rotated in the E direction, and in the case of FIG. 5C, the take-up roll 4 was rotated in the B direction, which sometimes caused a jam.

In view of the above, the present invention has been made in view of the above points, and a margin for designing an ink application pattern on an ink sheet is reduced as much as possible to provide a reliable ink sheet transport system without jam. The purpose is to provide a thermal printer.

[0017]

In order to solve the above-mentioned problems, in the present invention, the ink of the ink sheet is transferred to the image receiving paper, and acts on the ink sheet for recording on the image receiving paper. A thermal head, a platen for conveying the image receiving paper, a supply roll around which the ink sheet is wound, a take-up roll for winding up the ink sheet supplied from the supply roll, and the take-up roll. A drive means for applying a take-up torque is provided, and a torque limiter for giving a slip torque to the supply roll and between the drive means and the take-up roll is inserted. And a forward rotation preventing means provided on the supply roll.
Further, a control means for contacting and separating the forward rotation preventing means of the supply roll is provided.

[0018]

With the above-described structure, when the ink sheet is pinned, the image receiving paper is fed, or the image receiving paper is returned, the space between the supply roll and the take-up roll is increased. Completely controls / restrains the movement of the ink sheet, prevents the ink sheet once wound from being unwound, and can prohibit or allow rotation of the supply roll. Accordingly, it is possible to realize a thermal printer that can reliably carry the ink sheet without jamming without being pulled out.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 7A is a top view of the back tension applying section of the supply roll 5. In this figure, the supply roll 5
A groove portion 41 is formed on the end surface of the. On the other hand, the reel 42 shaped to fit in this groove is fixed to the main body frame 7 via the torque limiter 6, and the supply roll 5 can be attached and detached in the F direction in the drawing. 7 (b) and 7 (c) are views as seen from the F direction. As shown in this figure, the reel portion 42 has a ratchet mechanism including a ratchet 43 and a ratchet pawl 44. As shown in FIG. 7B, it rotates in the H direction but cannot reverse in the G direction.
Moreover, the solenoid 27 is fixed to the ratchet pawl 44 via the offset spring 46. When the solenoid 27 is excited, the ratchet pawl is released as shown in FIG. .. And this G
The supply of the ink sheet can be turned on / off by making the direction coincide with the supply / drawing direction of the ink sheet.

FIG. 8A is a top view of the winding mechanism portion of the winding roll 4. The structure is almost the same as that of the above-mentioned supply roll, except that a mechanism for transmitting the drive torque of the winding motor 9 to the torque limiter 8 via the pinion 47 and the gear 48 is provided, and the ratchet. There is no solenoid to turn on and off, and reverse rotation is always prevented. Therefore, if the J direction in FIG. 8B is made to coincide with the winding direction of the ink sheet, the once wound ink sheet 10 will not be unwound.

Next, the operation will be described with reference to the time chart of FIG. 9, the mechanism explanatory view of FIG. 1, and the operation explanatory diagrams of FIGS. As an initial operation, pinning for removing the slack of the ink sheet 10 is performed. As shown in FIG. 10B, the winding motor 9 is rotated in the normal direction in a state where the normal rotation of the supply roll 5 (direction E in FIG. 1) is prohibited without exciting the solenoid 27 for the supply roll 5. The roll 4 is rotated in the A direction to wind up the ink sheet, and after a certain period of time, it is stopped. As a result, since the rotation of the supply roll 5 is prohibited, a new ink sheet is not fed out and the state shown in FIG.
The state of (b) is realized.

As shown in FIG. 10C, the image receiving paper 3 is fed by rotating the platen 2 in the normal direction (direction C in the figure) by a driving means (not shown), and the image receiving paper 3 is composed of the platen 2 and the pinch roller 31. When a predetermined amount is fed from the joining point, the solenoid 27 is turned on to allow the feed roll to rotate normally, and then the conveyance path of the image receiving paper 3 is guided.
As shown in (d), the thermal head 1 is brought close to the platen 2 to feed the image receiving paper 3 around the platen, and thereafter, the solenoid is stopped to be excited to rotate the supply roll normally (in FIG. 10). E direction) is prohibited. When the head descends, the ink sheet is fed out, but the take-up roll 4 is prohibited from rotating in the reverse direction (direction B in the drawing) by the ratchet 49 and the ratchet claw 50, and the supply roll 5 rotates in the direction to pull out the ink sheet. In this process, the ink sheet 10 wound by the take-up roll 4 is permitted.
Will not be rewound, and the ink sheet 10 will always be fed from the supply roll 5.

Next, the edge of the image receiving paper 3 is detected and positioned by the edge sensor 19, but in order to eliminate the influence of the backlash of the paper feed drive system, FIG.
As shown in FIG. 11, the image receiving paper 3 is once passed through the edge sensor 19, and thereafter, as shown in FIG.
The image receiving paper 3 is pulled back until it passes 9 (the platen is rotated in the D direction in the drawing), and the platen 2 is reversed in the C direction as shown in FIG. 11C, and the positioning is performed when the edge sensor 19 detects an edge. To complete.

Next, the solenoid 27 is turned on to allow the supply roll 5 to rotate in the normal direction (direction E in the drawing), and then the ink sheet winding motor 9 is rotated in the normal direction to wind the ink sheet and detect the detection mark sensor. Yellow mark 1 by pair 18
When 5 is detected, the driving is stopped. As shown in FIG. 12 (a), the state of the solenoid remains the same, the supply roll 5 is allowed to rotate, the thermal head 1 is moved toward the platen 2, and the ink sheet 10 and the image receiving paper 3 are pressure-bonded at a prescribed pressure. Then, while sending the pixel information to the thermal head 1, the platen 2 is rotated in the direction C in the drawing at a prescribed speed, and at the same time, the ink sheet take-up motor 9 is rotated in the forward direction so that the Y component of the desired image is transferred onto the image receiving paper 3. Can be formed into.

When the printing of the Y component is completed, the data transfer to the thermal head 1, the normal rotation of the platen 2 and the driving of the ink sheet winding motor 9 are stopped, and the thermal head 1 is stopped.
To retreat. At this point, since the printing of the final line of the Y component has been completed, the ink sheet 10 and the image receiving paper 3 are in close contact with or in contact with each other (state of FIG. 12B), and the image receiving paper 3 is returned in this state and the head If the paper is ejected, a paper jam or an ink sheet jam will occur. Therefore, prior to the returning operation of the image receiving paper 3, the ink sheet is idly fed and the ink sheet is stretched (FIG. 12C). Therefore, the excitation of the solenoid 27 is released, the rotation of the supply roll 5 is prohibited, and the winding motor is rotated for a certain period of time, after which the pin tension is completed. Also at this time, since the rotation of the supply roll 5 is prohibited, the ink sheet is not pulled out from the supply roll with the pin tension operation.

Next, after allowing the normal rotation of the supply roll, the ink sheet winding motor 9 is normally rotated, and when the magenta mark 16 is detected by the detection mark sensor pair 18, the driving is stopped. Next, as shown in FIG. 12D, after the supply roll 5 is prohibited from rotating in the normal direction, the platen is rotated in the reverse direction (D direction) to return the image receiving paper 3 and position the print start position. In this process, the ink sheet 1
The movement of 0 is completely restrained between the supply roll 5 and the take-up roll 4, cannot be pulled out from either roll, and is temporarily pulled by static electricity such as image receiving paper. However, it is not pulled out.

The M component is printed by the same process as the Y component printing. In the same manner, the C component is printed, and after the ink sheet is pinned in the same manner as described above, the platen is rotated in the forward direction to eject the image receiving paper 3, and the series of operations is completed. Next, another embodiment will be described.

FIG. 13A is a top view showing another embodiment of the back tension applying section of the supply roll 5. In this figure, a groove 41 is formed on the end surface of the supply roll 5. On the other hand, a reel having a shape that fits in the groove 41 is fixed to the main body frame 7 via the torque limiter 6. A gear A55 is formed on the reel portion, and an electromagnetic brake 57 is connected to the gear A55 via a gear B56. By turning the brake 57 on and off, the rotation of the supply roll can be controlled. ing.

FIG. 14 is a top view showing another embodiment of the winding mechanism portion of the winding roll 4. Figure 8 shows the general structure
This is the same as the case of using the ratchet mechanism of No. 1, and instead of the ratchet, the one-way clutch 51 is used for the take-up reel 4
2 and the torque limiter 8, and the rotation stopper 5
2 is locked to the body frame 7. Here, if the lock direction of the one-way clutch is set as shown in FIG. 14B, the take-up reel can freely rotate in the take-up direction (direction A in FIG. 14B), but the ink sheet can be unwound. It cannot rotate in the direction (direction B). In addition,
The lock direction referred to here is a direction in which the take-up reel 42 is locked and locked when the outer ring of the one-way clutch is rotated.

Next, the time chart of FIG. 9 and FIGS.
The operation will be described with reference to the operation explanatory diagram. As an initial operation, as shown in FIG. 10B, pinning for removing the slack of the ink sheet 10 is performed. While the electromagnetic brake 57 connected to the supply roll 5 is turned on and the normal rotation of the supply roll 5 (rotation in the E direction in FIG. 10B) is prohibited, the winding motor 9 is rotated in the normal direction and the ink is wound by the winding roll 4. Sheet 1
Wind up 0 and stop after a certain time. As a result, the state of FIG. 10B is realized without newly feeding the ink sheet 10 from the supply roll 5.

In the state of FIG. 10 (b), the platen 2 is rotated in the normal direction (direction C in FIG. 10 (c)) by the driving means (not shown) to feed the image receiving paper 3, and then FIG. 10 (d). As shown in FIG. 4, the electromagnetic brake 57 is turned off to allow the supply roll 5 to rotate in the normal direction (rotation in the direction E in the figure), and then the thermal head 1 is brought into a substantially pressure-bonded state in order to guide the conveyance path of the image receiving paper 3. The image receiving paper 3 is fed around the platen while being brought close to the platen 2 until the above. When the head descends, the ink sheet 10 is fed out, but the one-way clutch 51 prohibits the reverse rotation (rotation in the B direction in the drawing) of the winding roll 4, and the supply roll 5 rotates in the normal rotation (E direction in the drawing). Since the ink sheet 10 wound by the take-up roll 4 is not rewound in this process, the ink sheet 10 is always paid out from the supply roll 5.

Next, the edge of the image receiving paper 3 is detected and positioned by the edge sensor 19, but in order to remove the influence of the backlash which the paper feed drive system has, FIG.
As shown in FIG. 11, the image receiving paper 3 is once passed through the edge sensor 19, and thereafter, as shown in FIG.
The image receiving paper 3 is pulled back until it passes 9 (the platen is rotated in the D direction in the drawing), and the platen 2 is reversed in the C direction as shown in FIG. 11C, and the positioning is performed when the edge sensor 19 detects an edge. To complete.

Next, the normal rotation of the supply roll (rotation in the direction E in the figure) is allowed with the electromagnetic brake 57 kept off,
The ink sheet take-up motor 9 is rotated in the forward direction to wind the ink sheet 10, and the detection mark sensor pair 18 is used to perform Y
The drive is stopped when is detected. As shown in FIG. 12A, while the state of the electromagnetic brake remains the same, the thermal head 1 is moved toward the platen 2, and the ink sheet 10 is moved.
By pressing the image receiving paper 3 and the image receiving paper 3 at a specified pressure, the platen 2 is rotated in the direction C in the drawing at a specified speed while sending pixel information to the thermal head 1, and at the same time, the ink sheet winding motor 9 is normally rotated. The Y component of the image can be formed on the image receiving paper 3.

When the printing of the Y component is completed, the data transfer to the thermal head 1, the normal rotation of the platen 2 and the driving of the ink sheet winding motor 9 are stopped, and the thermal head 1 is stopped.
To retreat. At this point in time, as shown in FIG. 12B, the last line of the yellow component has been printed, so the ink sheet 10 and the image receiving paper 3 are in close contact with or in contact with each other. If the paper is ejected, a paper jam or a jam of the ink sheet 10 will occur. Therefore, prior to the returning operation of the image receiving paper 3, the ink sheet is idly fed and the ink sheet is stretched (FIG. 12C). Therefore, the electromagnetic brake 57 is turned on, the rotation of the supply roll 5 is prohibited, and the winding motor is rotated for a certain period of time, after which the pin tension is completed. Also at this time, since the rotation of the supply roll is prohibited, the ink sheet is not pulled out from the supply roll with the pin pulling operation.

Next, after releasing the electromagnetic brake and allowing the normal rotation of the supply roll, the ink sheet take-up motor 9 is normally rotated, and when the magenta mark 16 is detected by the detection mark sensor pair 18, it is driven. Stop. The electromagnetic brake is applied to prohibit the forward rotation of the supply roll, and then the platen is rotated in the reverse direction to return the image receiving paper and position the print start position. In this process, the movement of the ink sheet 10 is completely restricted between the supply roll 5 and the take-up roll 4, and the ink sheet 10 cannot be pulled out from either roll, and is temporarily pulled by static electricity such as image receiving paper. It will not be pulled out even if a force to exert it acts.

The printing of the M component is performed by the same process as the printing of the Y component. In the same manner, the C component is printed, and after the ink sheet is pinned in the same manner as described above, the platen 2 is rotated in the forward direction, the image receiving paper 3 is ejected, and the series of operations is completed.

[0037]

As described above, according to the present invention,
Since the winding roll is provided with a reverse rotation preventing means, the supply roll is provided with a forward rotation preventing means, and further, a control means for connecting and disconnecting the forward rotation preventing means of the supply roll is provided, so that the initial setting operation of the thermal printer is performed. As a result, when the ink sheet is pinned, the ink sheet is not fed out from the supply roller side, and therefore it greatly contributes to the reduction of the margin when designing the ink application pattern of the ink sheet.

When the image receiving paper is fed or returned, the movement of the ink sheet is restricted between the supply roll and the take-up roll, and the ink sheet cannot be pulled out from either roll. Therefore, it is possible to prevent the ink sheet from being pulled out due to the influence of static electricity or the like, and prevent the ink sheet from being jammed.

[Brief description of drawings]

FIG. 1 is a mechanism explanatory view showing an embodiment of a thermal printer according to the present invention.

FIG. 2 is a perspective view showing a configuration of a conventional thermal printer.

FIG. 3 is a diagram illustrating an example of an ink sheet pattern.

FIG. 4 is an operation explanatory diagram of the thermal printer.

FIG. 5 is an operation explanatory diagram of the thermal printer.

FIG. 6 is a diagram illustrating the operation of the thermal printer.

FIG. 7 is an explanatory diagram showing an example of a tension applying unit for a supply roll according to the thermal printer of the present invention.

FIG. 8 is an explanatory diagram showing an example of a driving force applying section for the winding roll according to the thermal printer of the present invention.

FIG. 9 is a time chart showing the printing operation of the thermal printer of the present invention.

FIG. 10 is an operation explanatory diagram of the thermal printer of the present invention.

FIG. 11 is an operation explanatory diagram of the thermal printer of the present invention.

FIG. 12 is an operation explanatory view of the thermal printer of the present invention.

FIG. 13 is an explanatory diagram showing another embodiment of the tension applying section for the supply roll according to the thermal printer of the present invention.

FIG. 14 is an explanatory diagram showing another embodiment of the driving force applying section for the winding roll according to the thermal printer of the present invention.

[Explanation of symbols]

 1 Thermal Head 2 Platen 3 Image Receiving Paper 4 Winding Roll 5 Supply Roll 6 Torque Limiter 8 Torque Limiter 10 Ink Sheet 18 Mark Detection Sensor 19 Edge Sensor 27 Solenoid 31 Pinch Roller 32 Pinch Roller 43 Ratchet 44 Ratchet Claw 51 One Way Clutch 57 Electromagnetic Brake

Claims (1)

[Claims] 1. A thermal printer 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 and recording is performed on the image receiving paper. In order to perform, a thermal head acting on the ink sheet, a platen for conveying the image receiving paper, a supply roll around which the ink sheet is wound, and a winder for winding the ink sheet supplied from the supply roll. A take-up roll and a drive means for applying a take-up torque to the take-up roll are provided, and a torque limiter for giving a slip torque to the supply roll and between the drive means and the take-up roll is provided. The winding roll is provided with reverse rotation preventing means, and the supply roll is provided with forward rotation preventing means. Thermal printer, characterized in that the forward rotation preventing means Lumpur provided toward or away from the control unit.