JPS6071452A - Control of web taking-up direction and apparatus thereof - Google Patents

Abstract

PURPOSE:To smoothly correct the taking-up direction by supporting the revolution of a roll in the state where the top edge part of a succeeding web to be joined with the rear edge of a preceding web is pulled-out from the roll and operating a pulling force in the taking-up direction at the tep edge part of the succeeding web. CONSTITUTION:When a succeeding web X pulled-out from a web roll 2 is joined with a preceding web W, a brake force is applied onto a taking-up shaft 8, after the web X is pulled-out by a prescribed amount from the roll 2, and the revolution of the roll 2 is suspended or suppressed. Then, a negative pressure is generated in a suction box by the suction by a suction source, and after an attraction force is operated at the web top edge part Xa through an endless belt, said belt is transferred in the prescribed taking-up direction by revolving a guide roll. Then, the taking-up direction of the top edge part Xa is gradually corrected by the partial force f2 in the horizontal direction which is generated on the basis of the pulling force F in the prescribed taking-up direction, and the web is corrected to the prescribed takin-up state H1 from an aslantly deflected state H2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the direction of web unwinding in a web unwinding machine used in various web processing apparatuses for processing long strips such as paper, plastic films, metal foils, etc. It is related to the device.

In general, in various web processing devices that process long strips of paper, plastic film, metal foil, etc. (hereinafter simply referred to as ``webs''), the web being processed is When the feeding of the new web is completed, the front end of a new web is joined to the rear end of the web being processed, and the new web is continuously fed out for processing.

As web joining methods, the overlap joining method and the butt joining method are conventionally known, and these joining methods are selected depending on the type of processing work, for example, when the processing work is coating processing or printing processing. The butt joint method is used. In one example of this butt joining method, the leading end of a new web to be joined is fixed by suction onto a splice board having a large number of suction holes on a flat surface, and then cut along cutting grooves provided on the surface of the splice board. The tip of the new web is cut by a blade, unnecessary parts are removed, and the edges are trimmed. When the web being processed is finished being fed out, the rear end of the web being processed is fixed to the splice board by suction. death,
Cut the trailing edge of the web using a cutting blade along the cutting groove, remove unnecessary parts, and smooth the edge, and separate the trailing edge of the web being processed from the cutting groove as a boundary. A joining tape is applied to these parts in a state in which the leading edges of the webs are abutted against each other to join them. The splice board is usually provided with a regulating plate that regulates the widthwise position of the web, and the operator abuts the side edges of both the web being processed and the new web against this regulating plate. The unwinding direction of the new web is regulated, and at the same time both webs are aligned in the width direction and joined. Almost no displacement occurred in the width direction.

By the way, in this type of butt joining method, a device called an accumulator was conventionally used to temporarily stop the feeding of the web being processed during the joining process, which stopped the conveyance of the web and interfered with the continuous processing of the web. ,
This accumulator does not stop the conveyance of the web to the processing device, but only temporarily stops the feeding of the web.

However, this accumulator is composed of a large number of guide rolls, and for example, when the web is a photographic film whose surface is coated with a photosensitive material,
Scratches caused by contact between the guide roll and the web and damage due to static electricity occur, causing film failure, and a great deal of effort and time is wasted in maintaining the guide roll.

Recently, however, a welding apparatus has been developed which is capable of butt welding without stopping the feeding of the web during processing, as disclosed in Japanese Unexamined Patent Publication No. 55-74940. What is required of webs spliced using such a web splicing device is that the side edges of the web being processed and the side edges of the new web match at the splicing section, that is, the position of the side edges There should be no misalignment. The reason for this is that web processing equipment is usually equipped with a known web guide to prevent meandering conveyance of the web, but if the side edges of the web are misaligned at the web joint, the joint When the web passes through the web guide, unreasonable stress is generated on the web, causing problems such as breakage of the joint or wrinkles at the joint. For example, especially when the web processing device is a coating machine. In such cases, the coating liquid may adhere to the backing roller due to misalignment at the joint, causing serious quality problems.

A similar problem occurs when the unwinding direction of a new web is deviated from the planned direction.

By the way, as a web unwinding method for supplying the web to the web butt splicing device, an unwinding machine is known in which the entire unwinding machine is slid in the width direction of the web to control the widthwise position of the web. When such an unwinding method is used, the following problems occur.

First, the widthwise position of the web roll for the web being processed and the widthwise position of the web roll for the new web are generally not necessarily the same, and in this case, the entire unwinding machine is Since the relative relationship between the widthwise positions of both webs does not change even if the webs are controlled by moving, it is therefore impossible to match the positions of the side edges of both webs at the joint.

In M2, the web is emptied from the unwinding machine because the entire unwinding machine is constantly sliding in the width direction of the web without being controlled according to the deviation of the widthwise position of the web during processing. When the unwinding shaft is removed and a new web is wound on the unwinding shaft, it is very difficult to perform these tasks automatically.〇The second problem mentioned above. In order to solve this problem, when removing or installing the unwinding shaft, it is necessary to temporarily stop the sliding of the unwinding machine or to prevent the unwinding shaft from being unrolled by the empty unwinding shaft carrier and the new web. Proposals have been made to provide a sliding mechanism on the carrier for the rotated unwinding shaft so that the carrier follows the sliding movement of the unwinding machine, but in the former case, the unwinding Since the sliding movement of the machine is temporarily stopped, the widthwise position of the web being processed is not controlled during this stop period, which adversely affects the processing of the web in the web processing device.
In the latter case, the disadvantage is that the structure of the transport vehicle is complicated and the equipment cost is high.

On the other hand, if a new web is pulled out from a web roll but its unwinding direction is deviated from the planned unwinding direction (direction perpendicular to the unwinding axis of the web roll), There is no known effective means for correcting the direction.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to ensure that the direction of the leading end portion of the new web to be joined, which is pulled out from the web roll, ie, the unwinding direction, is the same as that of the planned winding. A method for controlling the unwinding direction of a web that can smoothly correct the deviation from the unwinding direction, and that can automatically achieve this method with a simple configuration and can join the web with high efficiency. The object of the present invention is to provide a device that allows the process to be carried out with high efficiency.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, W indicates the preceding web being processed and being fed out from the web roll 1 wound around the first unwinding shaft 7 to a web processing device (not shown), X
indicates a new subsequent web that is joined to the rear end of the web W being processed and is then fed out after the feeding of the web W being processed is completed, and this new web X is the second unwinding web. The tip portion Xa and the portion following this are in a state of being pulled out from the web roll 2 wound around the shaft 8.

3 indicates the rotation axis of the turret type web unwinding machine UW';
This pivot shaft 3 is rotatably supported at both ends in a frame 4.4' via a bearing unit 5.5'. The center part of the pivot shaft 3 is composed of a hollow pipe 301 having a prismatic shape, and the shaft end parts 300 and 300' supported by the pairs 5 and 5' are constructed in a cylindrical shape, and furthermore, one shaft The end portion 300 is a hollow shaft having a hollow portion 24 passing through the end portion 300 in the axial direction. This shaft end 3
A rotary joint 6 is fixed to 00, and a hydraulic tank (not shown) is attached to this rotary joint 6.
a connection port 23a for connecting four hydraulic pipes from the
23b.

23c, 23d and later-described hydraulic cylinders 21A, 21B
Connection port 23a' for connecting hydraulic piping from.

23b', 23c', and 23d' are provided, and each of these connection ports 23a, 23b, 23c, and 23d is a connection port 23a'.

23b', 23c', and 23d' inside the rotary joint 6. A slip ring (current collection ring, not shown) is attached to the other shaft end 300' of the rotating shaft 3, and electrically connects the electric equipment inside the unwinding machine UW with an external control device. has been done.

Further, an electric motor (not shown) for driving rotation of the pivot shaft is connected to this shaft end 300'.

Both ends of the Ml unwinding 4IB7 are held between a movable chucking nose 9A and a stationary chucking nose IOA, each having a conical tip. The moving side chucking nose 9A is the moving side bearing platen) I
The shear cylinder (not shown) etc. is connected to the IA unwinding shaft 7.
The shaft is rotatably supported so as to be able to reciprocate in the axial direction of the shaft. On the other hand, the stationary side chucking nose IOA is rotatably supported by the stationary side bearing bracket 12A. . A magnetic powder brake 13A for tension control is attached to this fixed flllllll bearing plattern A, and this magnetic powder brake 13 is keyed to the fixed side chucking nose l0AO shaft end.

Moving side bearing bracket IIA and fixed side bearing platen) 1
2A is connected and integrated with the support 14A. At the bottom of each of these moving side bearing platen) IIA and fixed side bearing platen) 12A are sliding bearings 15A, 15.
A is installed, and these sliding bearings 15A, 15A
is slidably mounted on bearing guides 16A, 16A which are fixed to the pivot shaft 3 along the length direction of the pivot shaft 3.

For safety, stoppers 17A and 17A are attached to both ends of the bearing guides 16A and 16A, respectively.

A web traveling position adjusting mechanism, for example, a hydraulic cylinder 21A is fixedly provided on the pivot shaft 3 from brackets 22A and 22AK, and a clevis-type attachment 2OA is attached to the tip of the piston rod 210A of the hydraulic cylinder 21A.
This attachment 20A is connected to a connecting pin 18AK supported by a bracket 19A attached to the lower part of a fixed side bearing bracket 12A.

The configuration related to the second unwinding shaft 8 is also similar to the configuration related to the first unwinding shaft 7 described above, and the same thing is indicated by substituting the numeral B in place of the numeral A.

An opening 25 is provided in the center of the pivot shaft 3.
Connection port 23a of rotary joint 6.

2ab', 23c/, and 23d' are connected to the hollow part 24 of the shaft end 300 of the pivot shaft 3.
The hydraulic cylinders 21A, 21 are drawn out from the hollow pipe 301 through the opening 25 through the inside of the hollow pipe 301.
B, connection ports 238″, 23b″, 23c″, 23d#
are connected to each.

Reference numeral 26 indicates a web drawing device for drawing out a new web, and this web drawing device 26 is provided at a position in front of the unwinding shaft 8 of the web roll 2, and has a large number of suction holes 3 on the soil surface.
A suction box 29 in the shape of a hollow box having a diameter of Four guide rolls 31 stretched around the suction box 29 to move it in the exit direction
This guide roll 31 is attached to a machine frame (not shown). The inside of the suction box 29 is connected to a suction source (not shown) such as a suction pump, and the suction force of the suction box 29, i.e., the internal pressure of the suction box 29, can be adjusted at least between "strong" and "weak" by appropriate means. It is configured so that it can be switched to two stages: "Strong" and "Strong".
The magnitude of the suction force when the switch is made is such that the new web placed on the upper surface of the suction box 29 via the endless belt 27 can be brought into close contact with the endless belt 27 and conveyed at the same speed. be enlightened,
The magnitude of the suction force when switched to "weak" is set to such a magnitude that the endless belt 27 slides on the lower surface of the tip portion Xa of the web X when the rotation of the web roll 2 is suppressed. A driving electric motor (not shown) is connected to one of the guide rolls 31.

Reference numeral 32 denotes a first detection mechanism that detects the widthwise position of the web W being fed out from the web roll 1 wound around the unwinding shaft 7, and this first detection mechanism 32 is shown in FIG. A preset web running position indicated by a dashed line in FIG.
A plurality of sensors, such as a pneumatic sensor, are disposed opposite each other via the web pull-out device 26.

Reference numeral 33 indicates a second detection mechanism for detecting the position in the width direction of the new web X that is fed out from the web roll 2 wound around the unwinding shaft 7, and this second detection mechanism 33 is shown in FIG. As shown in conjunction with FIG. It is provided so that it is possible to exit from the standby area PX.

35 and 36 are guide rolls rotatably supported on a machine frame (not shown).

The first detection mechanism 32 and the second detection mechanism 33 are
A hydraulic pressure adjustment mechanism (not shown) is connected to be controlled by these detection signals, and in the state shown in FIGS. 1 and 2, based on the detection signals from the first detection mechanism 32, The hydraulic cylinder 21A associated with the unwinding shaft 7 is activated, and the hydraulic cylinder 21B associated with the unwinding shaft 8 is activated based on the detection signal 1c from the second detection mechanism 33.
When the rotating shaft 3 rotates 180 degrees and the positions of the unwinding shafts 7 and 8 are reversed, an automatic switching mechanism (not shown) switches the positions of the unwinding shafts 7 and 8 to the upper unwinding shaft 8. The hydraulic cylinder 21B is activated based on the detection signal from the first detection mechanism 32, and the hydraulic cylinder 21A associated with the unwinding shaft 7 located at the bottom is activated based on the detection signal from the second detector s33. In response to each detection signal, the unwinding shaft associated with the detected web is moved in a direction opposite to the direction in which the side edge of the web is deviated from the web running position 34. Hydraulic cylinders associated with each unwinding shaft are operated to cause the unwinding shaft to move.

In the above configuration, the web W being unwound from the web roll 1 where the web is unwound as shown in e2 is guided by the guide roll 35, and passed through the first detection mechanism 32 to the web processing device. The web W is transported there and processed there. In the first detection mechanism 32, when the right edge WR of the web W is deviated leftward by a distance from the web running position 34, for example as shown in FIG.
The hydraulic cylinder 21A is actuated to attract the piston rod 210A in response to the detection signal from the outside, and as a result, the bearing brackets IIA and 12A slide together on the bearing guides 16A and 16A, and the unwinding shaft 7 becomes the pivot shaft. 3 to the right along the length direction. As the unwinding shaft 7 moves, the web W moves to the right in the width direction, and the right fIO edge WR of the web W moves to the web running position 34.
When it matches, the detection signal obtained at this time stops the operation of the hydraulic cylinder 21A, and the web W is conveyed with its right side iWR matching the web running position 34. When the right edge WR of the web W is deviated in the opposite direction to the above case, that is, in the right direction, the detection mechanism 32
The hydraulic cylinder 21A is actuated to extend the piston rod 210A in response to the detection signal of When the web W starts to move to the left in the width direction and the right edge WR of the web W coincides with the web running position 34, the detection signal obtained at this time stops the operation of the hydraulic cylinder 21A, and the web W
is conveyed with its right edge WR aligned with the web running position 34.

While the web W is being fed out, the leading end portion Xa of the web X drawn out from the web roll 2 mounted on the unwinding shaft 8 is placed on the web drawing device 26 via the guide roll 36. At this time, the second detection mechanism 33
has left the standby area PX. Web pulling device 26
The tip end Xa of the web X positioned above is not necessarily pulled out to the position shown by the broken line H1 in FIG. It is often pulled out in a state that is deviated obliquely from the perpendicular direction of 8, that is, in a state where the actual unwinding direction is misaligned with the planned unwinding direction. Position control including unwinding direction control of the web X pulled out in such a state will be described below. Web X
The magnetic powder brake 13B associated with the unwinding shaft 8 is excited by the position correction start signal, and a braking force is applied to the unwinding shaft 8 to stop the rotation of the web roll 2. The magnitude of this braking force is greater than the tensile force F caused by the suction of the web pulling device 26, which will be described later, when the internal pressure of the suction box 29 is "weak", and the internal pressure of the suction box 29 is "weak".
When the tension is "strong", it is weaker than the tensile force F caused by the suction of the web pull-out device 26.

Next, the inside of the suction box 29 is suctioned by the suction source to create a negative pressure, and a suction force is applied to the tip end Xa of the web X. The internal pressure is set to "weak". When the internal pressure of the suction box 29 reaches the internal pressure set to "weak", the driving electric motor is activated, causing the guide roll 31 to rotate (L, endless bell).
27 slides on the suction box 29 in the scheduled winding and exit direction. In this way, a tensile force F in the planned unwinding direction having a magnitude determined by the suction force applied through the through hole 28 of the endless belt 27 and the friction coefficient between the web X and the endless belt 27 is generated as shown in FIG. This occurs as shown below. This tensile force F is the tip portion Xa of the web
The unwinding direction of the end portion Xa of the web X is gradually corrected by this force f2, and the final Specifically, it is in the position shown by the broken line H1 in FIG. 3, that is, in a state where it is pulled out straight in the planned unwinding direction perpendicular to the unwinding shaft 8.

Next, the second detection mechanism 33 advances to the web running position 34. When the position in the width direction of the tip end portion Xa of the web X, that is, the position of the right side PIXR of the web
The hydraulic cylinder 21B operates to extend the bearing bracket 1113 and the bearing guide 16B.

1613J: i The unwinding shaft 8 slides and moves to the left along the length direction of the rotating shaft 3. Then, as the unwinding shaft 8 moves, the web X moves to the left in the width direction, and when the right edge XR of the web X coincides with the web traveling position 34, the detection signal obtained at this time causes the hydraulic cylinder 2
The operation of 1B is stopped, and the right edge XR of 1p is at the web running position 3411? (d) is controlled to match the condition. When the right side tdXR of the web
The hydraulic cylinder 21B is actuated to suck the piston rod 210Bl in response to the detection signal of At the same time, the web X starts to move to the right in the width direction, and when the right side 6 and XR of the web X coincide with the web running position 34, the detection signal obtained at this time stops the operation of the hydraulic cylinder 2113, and the web , the right side edge XR thereof is controlled to match the web running position 34.

In this way, when the position of the right edge XR of the web X coincides with the web running position 34, the rotation of the guide roll 31 is stopped, and the web stand by.

Next, when the web roll 1 has almost finished being fed out and enters the web joining cycle.

The internal pressure of the suction box 29 is switched to a little over 1'', the old guide roll 31 is driven, and the endless belt 27 is accelerated to a speed equal to the conveyance speed of the Kuep W, thereby conveying the Shikuep X together with the endless belt 27. The web W and the web X are butt-joined by being sent to a welding machine.

When the joining of web W and web X is completed, the second detector I 11733 is removed from the waiting area PX of web X,
The rotating shaft 3 is rotated 180 degrees by the electric motor for rotating the rotating shaft, and the positions of the unwinding shafts 7 and 8 are exchanged, and the unwinding shaft 7, which is in the lower position, is removed and a new nib roll is installed in its place. It is attached and transferred to the next joining row. Then, as the rotation shaft 3 rotates 180 degrees, the supply paths of the detection signals from the first detection mechanism 32 and the second detection mechanism 33 are switched, and the cylinder 21A related to the unwinding shaft 7 is connected to the second detection mechanism 3.
The cylinder 21B associated with the unwinding shaft 8 is controlled by the detection signal from the first detector 1f'&a2.

As described above, according to the present invention, the web roll 2 related to the web X is
The unwinding direction is corrected by applying a tensile force in the planned unwinding direction to the lower surface in a state where the rotation is suppressed and further unwinding is prohibited, so the correcting action is This is done reliably and no excessive force is applied to the web X including the tip portion Xa, so there is no risk of wrinkles or damage to the web.

In addition, the web unwinding device has a belt that moves in a scheduled unwinding direction and a suction box or the like that applies suction force through this belt.
This can be achieved by reliably and automatically controlling the unwinding direction described above. In particular, by using the endless belt 27 formed with the through holes 2g, suction force is applied to each of the through holes 28 distributed over the entire lower surface of the tip portion Xa of the web X, and the suction action points of the through holes 28 are Since the web is moved in the intended unwinding direction and a tensile force is applied in that direction as a whole, the unwinding direction of the web is completely aligned with the intended unwinding direction.

In addition, by making it possible to switch the suction force generated by the suction machine so that the above-mentioned control of the unwinding direction is achieved when the suction force is set to a small value,
When the suction force is set high, the tip part Xa of the web
can be forcibly held and on standby or moved.

As described above, it is possible to control the unwinding direction of the nib X, and the unwinding shafts 7 and 8 are provided so as to be movable independently in the longitudinal direction,
and 8 are hydraulic cylinders 21A and 21B that are operated by detection signals based on the respective deviations of the webs W and X, which are fed out from Rikishima, from the set web running position 34 in the width direction. Since the movement of the webs W and L is controlled independently, the webs W and Both webs can be fed out in a state where the tip of a new web can be joined to the rear end of the new web without causing a positional shift in the direction of the two webs.Then, the empty unwinding shaft can be When removing and installing the unwinding shaft around which air has been newly wound, the movement of the unwinding shaft related to the removal and installation while continuing to control the widthwise position of the web being processed. Since only the third control can be stopped independently, the web being processed can be stably transported to the set running position, while the empty unwinding shaft can be removed and a new web can be wound. Installation of the unwinding shaft is done in step 1.
This can be done automatically with simple equipment. In addition, compared to the conventional case where the entire unwinding mechanism is made to slide, the hydraulic cylinder for the sliding drive only needs to be smaller, and the weight borne by the hydraulic cylinder is reduced, which reduces the control response. You can get advantageous points such as quick sex.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment and can be modified in various ways. For example, a pneumatic cylinder or an electric motor may be used instead of a hydraulic cylinder as a drive source for controlling the movement of the unwinding shaft. When the electric motor 411 is used, the rotary joint 6 and the hollow part at the shaft end 300 24. Although the opening 25 of the swing IJ13 is no longer necessary, the structure requires a current collection ring etc. for electrical wiring.Also, as the detectors a32 and 33, instead of pneumatic sensors, Waep's Depending on the type, a reflective phototube sensor may be used.In this case, if the sensor is installed inside the suction box 29, the movement of the web conveyance path due to the rotation of the pivot shaft 3 will not be obstructed, so the sensor can be used. The mechanism that allows it to move forward and backward is unsettling.

Further, in the embodiments described above, both the first unwinding shaft 7 and the second unwinding shaft 80 are provided movably and are configured to be able to independently control their movement, but the traveling position of the web is In cases where the relative positional relationship between the web W and the web X is not particularly set, the unwinding shafts 7 and 8
It is also possible to control only one of them movably; in this case, the unwinding shaft, which is movably provided, can be controlled at the running position of the web, which is related to the unwinding shaft, which is fixedly provided. The movement of a movably provided unwinding shaft may be controlled so that the running positions of the web coincide.

In addition, in cases where the running position of the web does not need to be set, if both unwinding shafts are provided with a movable location, the deviation of the web running position relative to each unwinding shaft will be approximately half the distance. Since it is only necessary to control the movement of each unwinding shaft, the advantage of fast control response speed can be obtained.

As described above, according to the present invention, when the unwinding direction of the leading end portion of the new read-behind web pulled out from the web roll and to be joined to the preceding web is deviated from the planned unwinding direction, This can be corrected smoothly and reliably, and can be done automatically, so that the web welding can be done with high working efficiency.

[Brief explanation of drawings]

Are Figures 1 and 2 an embodiment of the present invention? The explanatory front view, the explanatory 11111 side view, and FIG. 3 are explanatory diagrams schematically showing the state of the widthwise position of the web. 1.2... Web roll W, X... Web 7.8...
...Unwinding shaft 3...Swivel axis LIW...Turnot type extension ridge 4.4'...Frame 5.5'...Pairing unit 300.300'...Shaft end 301. ...Hollow pinhole...Rotary joint 21A, 21B...Hydraulic cylinder 9A, 9B...Moving side chucking nose IQA, I
QH...Fixed 9111 tracking nose 11A, I
IB...Moving side bearing bracket 12A, 12B...
Fixed side @ party bracket 13A, 13B... 5H powder pouring block V-key 14A, 14B... pillar 15A, 15B... sliding bearing 16A, 16B... bearing guide 17A, 17B
・・・Sto Tsunozo -22A, 22B...
Bracket 210A, 210B...Piston rod 2OA, 20
B... Acutements 19A, 19B... Brackets 18A, 18B... Connection bin 25... Opening part 24... Hollow part 26... Waep drawing device 30... Suction hole 29.
... Zakujo box 281 Shell hole 27 Endless belt 31 ... Guide roll 32 ... First detection (coal measure 33 ... Second detection vortex 34 ... Web running position PX ... Features Heading 35.36...Guide a-rule W R, Xit...Right side edge Xa...Tip portion Agent Patent attorney Tomohiko Oi (.

Claims (1)

[Scope of Claims] 1) The rotation of the web roll is suppressed in a state where the leading end portion of the trailing web to be joined with the trailing end of the trailing web is pulled out from the web roll, and in this state, the leading end portion of the trailing web is pulled out from the web roll. A method for controlling a web unwinding direction, comprising applying a tensile force to a surface in a scheduled unwinding direction perpendicular to the unwinding axis of the web roll. 2) Provided at a position in front of the unwinding shaft of the web roll. comprising a web pulling device for holding the pulled leading end portion of the trailing web to be joined with the trailing end of the leading web;
The web unwinding device includes a belt that moves in a predetermined unwinding direction perpendicular to the unwinding axis of the web roll, and a suction mechanism that applies suction force to the web positioned on the belt through the belt. A web unwinding direction control device comprising: 3) The suction force by the suction mechanism is variable, and when the suction force is small, the belt slides and moves with the web when the rotation of the unwinding shaft of the web roll is suppressed. web unwinding direction control device.