JP2011183461A - Sheet cutter and slit method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet cutter and a slit method for improving quality of the finally formed sheet. <P>SOLUTION: This sheet cutter includes a main feed roll 600 for carrying a sheet 400 to the rear by sandwiching the sheet between an outer peripheral surface of a rotating upper roller 601 and an outer peripheral surface of a rotating lower roller 602, a sub-feed roll 800 arranged in the rear of the main feed roll and carrying the sheet to the rear by sandwiching the sheet between an outer peripheral surface of a rotting upper roller 801 and an outer peripheral surface of a rotating lower roller 802, a slitter 700 arranged between the respective feed rolls and slitting the sheet so that a width of the sheet becomes a predetermined width, and servomotors (SM<SB>1</SB>and SM<SB>2</SB>) for controlling tension of the sheet 400 between the respective feed rolls by controlling a rotating speed and/or torque of the respective rollers. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet cutter for cutting a sheet with a slitter so that the width of the sheet such as paper or film becomes a predetermined width, and a method for cutting the sheet with a slitter.

  In a paper manufacturing factory or the like, manufactured continuously connected sheets of paper or film are wound into a roll and then shipped to a processing factory or the like. In a processing factory or the like, a roll-shaped sheet is supplied to a sheet cutter, slit (cut) so as to have a predetermined width, and then cut into a predetermined length. Thereby, a sheet having a predetermined width and a predetermined length is continuously formed. The configuration of such a conventional sheet cutter will be described with reference to FIGS.

  FIG. 6 is a schematic diagram illustrating a configuration of a sheet cutter according to the related art. FIG. 7 is a schematic diagram illustrating an unreel stand that holds a sheet wound in a roll shape and continuously supplies the sheet to a sheet cutter.

  An unreel stand 10 shown in FIG. 7 includes two support plates 12 fixed on a base member 11 at a predetermined interval, and a rotating shaft 13 rotatably attached between these support plates 12. And having. In FIG. 7, only one of the two support plates 12 is shown for convenience.

  The unreel stand 10 holds the roll-shaped sheet 20 rotatably by passing the rotary shaft 13 through a through hole formed at the center of the roll-shaped sheet 20. Further, the unreel stand 10 is provided with a brake 14 for braking against the rotation of the rotating shaft 13, that is, the rotation of the roll-shaped sheet 20.

  One continuous sheet 25 was taken out from the outer periphery of the roll-shaped sheet 20 and led to an auxiliary roll 30 having two rotatable rollers 31 and 32 as indicated by an arrow A. Then, it guide | induces in the direction shown by the arrow B, and is supplied to the sheet cutter shown in FIG.

  In the sheet cutter shown in FIG. 6, the sheet 25 supplied from the unreel stand 10 via the auxiliary roll 30 is guided to a lead-in roll 40 having two rotatable rollers 41 and rollers 42. The sheet 25 that has passed the lead-in roll 40 is continuously slit by the slitter 50 so that its width becomes a predetermined width. That is, the slitter 50 continuously cuts the sheet 25 using the rotating upper blade 51 and the rotating lower blade 52. The sheet 25 formed to have a predetermined width by the slitter 50 is directed to the feed roll 60.

The feed roll 60 has a rotatable upper roller 61 and a lower roller 62. The lower roller 62 rotates when supplied with power from the servo motor (SM ₁ ). The outer peripheral surface of the upper roller 61 is in contact with the outer peripheral surface of the lower roller 62. Therefore, the upper roller 61 rotates in synchronization with the rotation of the lower roller 62. The feed roll 60 conveys the sheet 25 backward by sandwiching the sheet 25 between the outer peripheral surface of the rotating upper roller 61 and the outer peripheral surface of the lower roller 62. As a result, when the feed roll 60 pulls the sheet 25, the sheet 25 is pulled from the roll-shaped sheet 20 held on the unreel stand 10 and conveyed via the auxiliary roll 30 and the lead-in roll 40. . That is, the feed roll 60 gives a moving force (running force) to the sheet 25.

  A rotary knife 70 is disposed behind the feed roll 60. The rotary knife 70 has a rotatable upper drum 71 and a lower drum 72. Blades 71a and 72a are formed on the outer peripheral surfaces of the upper drum 71 and the lower drum 72, respectively. Therefore, the blade 25a and the blade 72a press the sheet 25 at regular time intervals, whereby the sheet 25 is cut to a predetermined length. The cut sheet is guided by a conveyor unit 80 including a plurality of rollers and a belt, and is stored in the layboy 90 as a final sheet 28.

  However, in the above-described conventional sheet cutter, there is a problem that the shape of the surface (cut surface) cut by the slitter in the sheet is deteriorated, and the quality of the sheet as the final product is deteriorated. is there. Since the quality of the cut surface of the sheet is very important by the user who purchases and uses the product, such a problem is a fatal problem for a producer who produces the product and provides it to the user. It might be.

  Furthermore, when the sheet is cut by a slitter, paper dust (dust) is generated and scattered and adheres to the sheet. This is also a factor that deteriorates the quality of the sheet as a final product. For example, when a manufacturer or the like delivers printing paper with paper dust adhered to a printing company or the like as a user, when the printing company or the like performs printing directly on the printing paper, Since the paint does not adhere, white spots occur on the printed surface. Therefore, a printer or the like has to clean the printing paper before printing. Also, the paper dust adhering to the blanket of the printing press must be cleaned. As a result, the producer or the like receives an important claim from the printer or the like.

  The present invention has been made in view of such problems, and an object thereof is to provide a sheet cutter and a slitting method that improve the quality of a finally formed sheet.

  First, as a result of searching for the cause of the deterioration of the shape of the cut surface of the sheet, the present inventor has found that the shape of the cut surface deteriorates as the tension of the portion to be cut by the slitter in the sheet increases. .

  FIG. 1 is a sectional view conceptually showing a partially enlarged sheet and slitter when the sheet is slit by a slitter. FIG. 2 is a cross-sectional view conceptually showing an enlarged view of the cut surface of the sheet.

  The slitter shown in FIG. 1 has a plate-shaped blade 110 as an upper blade, and a saddle-shaped blade 120 as a lower blade. The scissors blade 120 has a scissors shape and rotates around the central axis 121. The dish-shaped blade 110 has a dish-shaped shape and rotates around a central axis (not shown). When the sheet 200 advances in the depth direction on the paper surface with respect to the rotating dish-shaped blade 110 and the saddle-shaped blade 120, the sheet 200 is cut so that the width becomes a predetermined width.

  As is clear from FIG. 1, the dish-shaped blade 110 bites into the sheet 200 as if a wedge is driven into the sheet 200. In this case, the greater the tension of the sheet 200, the greater the force with which the cut edge of the sheet 200 sandwiches the dish-shaped blade 110. In other words, the greater the tension of the sheet 200, the easier the cut end of the sheet 200 receives pressure (side pressure) from the side surface 111 and the side surface 112 of the dish-shaped blade 110. Therefore, the cut end of the sheet 200 is rubbed by each side surface of the dish-shaped blade 110, and sometimes it is torn from the middle of the shear cut. In this case, the sheet 200 is shear-cut up to a certain thickness 201, but is torn at the remaining portion 202. Thus, paper powder 210 is generated by tearing the remaining portion 202 of the sheet 200. Further, when focusing on the shear-cut portion 201 of the sheet 200, a good cut surface may be formed in a portion 201a of the portion 201 that is in contact with the side surface (belly side) 112 of the dish-shaped blade 110. However, the portion 201b in contact with the side surface (back side) 111 of the dish-shaped blade 110 is rubbed by the side surface 111 to become rough and generates paper dust.

  Such a tendency indicates that the greater the tension of the sheet 200, the thicker the thickness of the sheet 200, and further, the wrap amount of the dish-shaped blade 110 and the lower blade-shaped blade 120 (the length indicated by reference numeral 130 in FIG. 1). The larger the size, the stronger.

  In addition to the slitter shown in FIG. 1, not only the upper blade but also the lower blade as shown in FIG. 3 is used in the slitter shown in FIG. A similar trend is seen. However, in the example shown in FIG. 1, only one portion 200b of the sheet 200 that is separated by cutting is rubbed by the side surface (back side) 111 of the upper blade plate-type blade 110 to become rough. In the example shown in FIG. 3, not only one portion 200 b separated by cutting but also the other portion 200 a is rubbed by the side surface (back side) 111 of the lower blade plate-type blade 110.

  In order to solve such a problem, it is conceivable to reduce the tension of the sheet 200. Specifically, in the unreel stand 10 shown in FIG. 7, by controlling (reducing) the braking force by the brake 14, the sheet 25 in the portion slit by the slitter 50 in the sheet cutter shown in FIG. 6. It is conceivable to use a technique of reducing the tension of the sheet (making it an appropriate tension suitable for slitting). However, as apparent from the fact that the total length of the sheet cutter shown in FIG. 6 is usually about 40 to 50 m, when this method is used, the sheet 25 supplied from the unreel stand 10 is When traveling in the sheet cutter, sagging (distortion) occurs in the sheet 25, which causes wrinkles in the sheet 25. As a result, not only the sheet 25 cannot travel smoothly, but also the sheet 25 is slit by the slitter 50 in a state where wrinkles are generated, so that the cut surface of the sheet 25 is deteriorated.

  Therefore, the inventor causes the sheet 25 to travel while maintaining a sufficient tension that does not hinder the traveling of the sheet 25, and locally controls the tension of only the portion cut by the slitter in the sheet 25. Focused on. However, in the sheet cutter according to the prior art shown in FIG. 6, controlling the tension of the sheet 25 by the brake 14 of the unreel stand 10 integrally controls the tension of the sheet 25 in the entire machine. Therefore, such control cannot be realized.

  Accordingly, the present inventor arranges a main feed roll (first conveying means) that gives a running force to the sheet in front of the slitter, focusing on locally controlling the tension of only the slit portion of the sheet. Further, the present inventors have found a configuration in which a sub-feed roll (second conveying means) is disposed behind the main feed roll, and a slitter is disposed between the main feed roll and the sub-feed roll. According to this configuration, by adjusting the rotation speed and / or torque of the main feed roll, a sufficient tension that does not hinder travel is applied to the sheet from the unreel stand to the main feed roll. While the sheet tension can be controlled in this way, the rotation speed and / or torque of the sub-feed roll is adjusted in consideration of the relationship with the rotation speed and / or torque of the main feed roll (roll diameter, speed reducer ratio, etc.) By doing so, the tension of the sheet between the main feed roll and the sub-feed roll, that is, the tension of the sheet in the portion cut by the slitter can be controlled locally (independently).

  That is, the sheet cutter according to the present invention includes a rotating upper roller and a lower roller, and a first conveying unit that conveys the sheet between the outer peripheral surface of the upper roller and the outer peripheral surface of the lower roller and conveys the sheet backward. And a slit means that is arranged behind the first conveying means and cuts the sheet so that the width of the sheet is a predetermined width, and a roller that is arranged behind the slit means and rotates, By controlling at least one of the number of rotations and torque of each roller, the second conveying unit that conveys the sheet to the rear while contacting the outer peripheral surface of the roller, and the first conveying unit and the first And control means for controlling the tension of the sheet with the conveying means.

  Furthermore, the slitting method according to the present invention includes a step of sandwiching a sheet between the outer peripheral surfaces of each of the rotating first upper roller and the first lower roller and conveying the sheet backward, the first upper roller and the first The sheet that has passed through the lower roller is brought into contact with the outer peripheral surface of the rotating second roller and conveyed backward, and the sheet that has passed through the first upper roller and the first lower roller is the second roller. Cutting the sheet so that the width of the sheet becomes a predetermined width before passing through the sheet, and controlling at least one of the rotational speed and torque of each roller, And controlling the tension of the sheet between the first conveying means.

It is sectional drawing (1st example) which expands partially and shows a sheet | seat and a slitter in the case of slitting a sheet | seat with a slitter. It is sectional drawing which expands and shows the mode of the cut surface of a sheet | seat conceptually. It is sectional drawing (2nd example) which expands partially and shows a sheet | seat and a slitter in the case of slitting a sheet | seat with a slitter. It is a schematic diagram which shows notionally the structure of the sheet cutter which concerns on embodiment of this invention. It is a graph which shows the specific numerical example of the tension | tensile_strength of the sheet | seat between the main feed roll and sub feed roll in the sheet cutter which concerns on embodiment of this invention. It is a schematic diagram which shows the structure of the sheet cutter which concerns on a prior art. It is a schematic diagram which shows the unreel stand which hold | maintains the sheet wound by roll shape and supplies a sheet | seat continuously to a sheet cutter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic diagram conceptually showing the structure of the sheet cutter according to the embodiment of the present invention. The sheet cutter shown in FIG. 4 is supplied with continuously connected sheets 400 from, for example, an unreel stand 10 (see FIG. 7) that rotatably holds a sheet wound in a roll shape.

  The sheet 400 supplied from the unreel stand 10 is first guided to a lead-in roll 500 having a rotatable roller 501 and a roller 502. The lead-in roll 500 has a function of supporting and guiding the traveling of the sheet 400. An arbitrary number of rollers or the like for supporting and guiding the travel of the sheet 400 may be provided between the unreel stand 10 and the lead-in roll 500.

Behind the lead-in roll 500, a main feed roll (first conveying means) 600 that provides a running force to the sheet 400 is disposed. The main feed roll 600 has a rotatable upper roller 601 and a lower roller 602. The lower roller 602 rotates when power is supplied from the servo motor (SM ₁ ). The outer peripheral surface of the upper roller 601 is in contact with the outer peripheral surface of the lower roller 602. Therefore, the upper roller 601 rotates in synchronization with the rotation of the lower roller 602. The main feed roll 600 having such a configuration conveys the sheet 400 backward by sandwiching the sheet 400 between the outer peripheral surface of the rotating upper roller 601 and the outer peripheral surface of the lower roller 602. As a result, the main feed roll 600 pulls the sheet 400, whereby the sheet 25 is pulled from the roll-shaped sheet 20 held on the unreel stand 10 and travels through the sheet cutter via the lead-in roll 500. To do.

The number of rotations and / or torque of each roller of the main feed roll 600 is preferably set so that the sheet 400 does not sag (distortion) until the sheet 400 reaches the main feed roll 600 from the unreel stand 10. In order to ensure, it is controlled by adjusting the rotation speed and / or torque of the servo motor (SM ₁ ) and / or adjusting the braking force of the brake 14 of the unreel stand 10.
The rotation speed (in other words, rotation speed or peripheral speed) of each roller of the main feed roll 600 is increased or decreased by increasing or decreasing the frequency applied to the servo motor (SM ₁ ). On the other hand, the torque T of each roller of the main feed roll 600 increases or decreases the current I flowing through the servo motor (SM ₁ ) according to T = kI (where T: torque, I: current, k: coefficient). Increase or decrease. Thereby, the rotation speed and torque of each roller can be individually controlled by controlling the frequency and current applied to the servo motor (SM ₁ ).

  A slitter 700 that cuts (cuts) the sheet 400 is disposed behind the main feed roll 600 so that the width of the sheet 400 becomes a predetermined width. The slitter 700 continuously cuts the sheet 400 using the rotating upper blade 701 and lower blade 702. The slitter is composed of the upper blade plate type blade and the lower blade plate type blade shown in FIG. 1, the one formed of the upper blade plate type blade and the lower blade plate type blade shown in FIG. Can be used.

A sub-feed roll (second conveying means) 800 is disposed behind the slitter 700. The sub-feed roll 800 has a rotatable upper roller 801 and a lower roller 802. The lower roller 802 rotates when power is supplied from the servo motor (SM ₂ ). The outer peripheral surface of the upper roller 801 is in contact with the outer peripheral surface of the lower roller 802. Therefore, the upper roller 801 rotates in synchronization with the rotation of the lower roller 802. The sub-feed roll 800 having such a configuration conveys the sheet 400 backward by sandwiching the sheet 400 between the outer peripheral surface of the rotating upper roller 801 and the outer peripheral surface of the lower roller 802. In FIG. 4, a form in which the sub-feed roll 800 includes both the upper roller 801 and the lower roller 802 is shown as the most preferable embodiment. However, the present invention includes a form in which the sub-feed roll 800 includes only the lower roller 802 without using the upper roller 801. In this case, the sub-feed roll 800 conveys the sheet 400 backward by bringing the sheet 400 into contact with the outer peripheral surface of the rotating lower roller 802.

The rotation speed (in other words, rotation speed or circumferential speed) of each roller of the sub-feed roll 800 is increased or decreased by increasing or decreasing the frequency applied to the servo motor (SM ₂ ). On the other hand, the torque T of each roller of the sub-feed roll 800 increases or decreases the current I flowing through the servo motor (SM ₂ ) according to T = kI (where T: torque, I: current, k: coefficient). Increase or decrease. Thereby, the rotation speed and torque of each roller can be individually controlled by controlling the frequency and current applied to the servo motor (SM ₂ ).

The servo motor (SM ₁ ) and the component (control means) that controls the servo motor (SM ₂ ) include, for example, a frequency inverter that changes the frequency applied to each servo motor, and a current that flows through each servo motor. A current limiting circuit and the like are included.

The sub-feed roll 800 can control the tension of the sheet 400 between the sub-feed roll and the main feed roll 600, that is, the tension of the sheet 400 that is cut (slit) by the slitter 700. Specifically, the sub-feed roll 800 controls the tension of the sheet 400 slit by the slitter 700 so as to be smaller than the tension of the sheet 400 guided to the main feed roll 600.
One method for realizing such control is to change the difference between the rotation speed of each roller of the sub-feed roll 800 and the rotation speed of each roller of the main feed roll 600. The rotation speed of each roller of the sub-feed roll 800 is set to be appropriately larger than the rotation speed of each roller of the main feed roll 600. In this state, by reducing the rotation speed of each roller of the sub-feed roll 800 to reduce the difference between the rotation speed of each roller of the main feed roll 600, the sub-feed roll 800 and the main feed roll 600 can be reduced. The tension of the sheet 400 can be reduced. Conversely, by increasing the number of rotations of each roller of the sub-feed roll 800 to increase the difference between the number of rotations of each roller of the main feed roll 600, the sheet between the sub-feed roll 800 and the main feed roll 600 is increased. The 400 tension can be increased.

As one specific example, the number of rotations of each roller of the main feed roll 600 is detected, and the ratio of the number of rotations to the number of rotations of each roller of the sub-feed roll 800 becomes a predetermined ratio. It controls the rotation of 800 servo servo motors (SM ₂ ). Any given ratio can be used. Preferably, a ratio such that the rotation speed of each roller of the sub-feed roll 800 is increased by about 0.01 to 0.1% with respect to the rotation speed of each roller of the main feed roll 600 can be used. More specifically, when paper is used as the sheet 400, the rotation speed of each roller of the sub-feed roll 800 is about 0.0 N% (N is 1 or more) with respect to the rotation speed of each roller of the main feed roll 600. A ratio that increases by a natural number) can be used. Further, when a film is used as the sheet 400, the rotation speed of each roller of the sub-feed roll 800 is only about 0. A ratio that increases can be used.

In addition to controlling the number of rotations of each roller (also referred to as “draw control”), the tension of the sheet 400 between the feed rolls can also be controlled by controlling the torque of each roller. That is, by changing the difference between the torque of each roller of the sub-feed roll 800 and the torque of each roller of the main feed roll 600 (also referred to as “torque control”), the tension of the sheet 400 between the feed rolls is controlled. be able to.
First, the torque of each roller of the sub feed roll 800 is set appropriately larger than the torque of each roller of the main feed roll 600. In this state, by reducing the torque of each roller of the sub-feed roll 800 and / or increasing the torque of each roller of the main feed roll 600, the difference in torque between the feed rolls can be reduced. Thus, the tension of the sheet 400 between each feed roll can be reduced. Conversely, the torque difference between the feed rolls can be increased by increasing the torque of each roller of the sub-feed roll 800 and / or decreasing the torque of each roller of the main feed roll 600. Thus, the tension of the sheet 400 between each feed roll can be increased.

When a material that cannot be stretched when pulled (such as paper) is used as the sheet 400, such material may be torn if only the draw control is used. Therefore, when using such a material, it is preferable to use torque control in addition to draw control.
On the other hand, when a material (for example, an optical film) that can be stretched when it is pulled is used as the sheet 400, it is unlikely that such a material is torn, so that only the draw control can be used. It goes without saying that torque control can be used in addition to draw control even when such a material is used.

  A rotary knife 900 is disposed behind the sub-feed roll 800. The rotary knife 900 has a rotatable upper drum 901 and lower drum 902. Blades 901a and 902a are formed on the outer peripheral surfaces of the upper drum 901 and the lower drum 902, respectively. Thus, the sheet 400 is cut into a predetermined length by the blade 901a and the blade 902a pressing the sheet 400 at regular time intervals. The cut sheet is guided by a conveyor unit 1000 including a plurality of rollers and a belt, and is stored in the layboy 1010 as a final sheet 410.

  As described above, according to the present invention, the tension of the sheet 400 guided to the main feed roll 600 is slackened (distorted) in the sheet 400 by adjusting the rotation speed and / or torque of each roller of the main feed roll 600. The tension can be controlled so as not to occur. Further, by adjusting (increasing or decreasing) the difference in the rotational speed and / or torque between each roller of the sub-feed roll 800 and each roller of the main feed roll 600, the main feed roll 600 and the sub-feed roll 800 are adjusted. The tension of the sheet 400 can be controlled locally (individually) so that the tension of the cut surface of the sheet 400 is good.

  Next, a specific numerical example of the tension of the sheet 400 between the main feed roll 600 and the sub-feed roll 800 in the sheet cutter according to the embodiment of the present invention is shown in FIG. In FIG. 5, the horizontal axis indicates the density of the sheet 400 (one sheet) used, and the vertical axis indicates the tension of the sheet 400.

According to this graph, when a general copy sheet (density about 80 [g / m ² ]) is used as the sheet 400, the tension of the slit portion of the sheet 400 is about 45 [g / mm]. That is, about 0.45 [kg / cm]. Further, when newspaper (density 30 [g / m ² ]) is used as the sheet 400, the tension of the slit portion of the sheet 400 is about 20 [g / mm], that is, about 0.2 [kg / m]. cm].

  On the other hand, when the sheet cutter according to the prior art shown in FIG. 6 is used, as the tension of the slit portion of the sheet, ensure a sufficient tension that does not sag (strain) the traveling sheet. For the above-mentioned reason that it is unavoidable, a tension of about “twice” that shown in FIG. 5 is required. In fact, the slit is made on the sheet while securing such a large tension. This means that according to the present invention, the tension of the slitted portion of the sheet can be reduced to about half of the tension required by the prior art. Thereby, according to this invention, the shape of the cut surface in a sheet | seat can be made favorable compared with a prior art.

  In the present embodiment, the case where one continuously connected sheet supplied from one unreel stand is sent to the slitter has been described, but actually, the slitter includes a plurality of sheets. In some cases, the sheets are stacked and sent to a slitter. In this case, preferably, the tension calculated by multiplying the tension shown in FIG. 5 by N can be used as the tension of the slit portion in a plurality (N) of sheets.

  The present inventor has found that the reason why the shape of the cut surface in the sheet is deteriorated is that the tension of the sheet is high, so that the tension of the slit portion in the sheet is locally reduced. We were able to reach the technical idea of the present invention. That is, those skilled in the art have not yet recognized that the deterioration of the shape of the cut surface of the sheet is caused by the tension of the sheet. Thus, those skilled in the art cannot even conceive of reducing the tension of the sheet.

  Furthermore, those skilled in the art cannot turn to the direction of decreasing the tension of the sheet due to the following circumstances. That is, when the tension of the sheet is small, (1) sagging (distortion) is generated in the sheet, and wrinkles are generated in the sheet during traveling. (2) the slit by the slitter meanders in the sheet. Various problems occur, such as an error in the flow dimension in In particular, when wrinkles occur in the traveling sheet, the shape of the slit by the slitter in the sheet deteriorates, and such a sheet has a fatal defect as a final product. Thus, those skilled in the art take care to ensure a sufficiently large tension in the sheet so that such problems do not occur. Therefore, even those skilled in the art cannot follow the idea of reducing the tension of the sheet.

  In the present invention, the shape of the cut surface (cut surface) in the slit sheet is regarded as important, and the generation of paper dust (dust) due to the slit is regarded as a problem. Printing paper and IT related materials (for example, polarizing plates, optical films, And suitable for application in the field of lithium ion battery electrode materials and the like.

600 Main feed roll (first transport means)
601 Upper drum 602 Lower drum SM ₁ Servo motor 700 Slitter 701 Upper blade 702 Lower blade 800 Sub-feed roll (second conveying means)
801 Upper drum 802 Lower drum SM ₂ Servo motor

Claims (5)

A first conveying means that has an upper roller and a lower roller that rotate, sandwiches the sheet between the outer peripheral surface of the upper roller and the outer peripheral surface of the lower roller, and conveys the sheet backward;
Slit means disposed behind the first conveying means for cutting the sheet so that the width of the sheet is a predetermined width;
A second conveying means disposed behind the slit means, having a rotating roller, and abutting the outer peripheral surface of the roller to convey the sheet backward;
Control means for controlling the tension of the sheet between the second conveying means and the first conveying means by controlling at least one of the rotational speed and torque of each roller;
A sheet cutter comprising:   The control means performs at least one of decreasing the rotation speed of the roller of the second transport means and increasing the rotation speed of the roller of the first transport means, The sheet cutter according to claim 1, wherein the sheet tension between the second conveying unit and the first conveying unit is reduced.   The control means executes at least one of decreasing the torque of the roller of the second transport means and increasing the torque of the roller of the first transport means, thereby The sheet cutter according to claim 1 or 2, wherein the tension of the sheet between the two conveying means and the first conveying means is reduced. The second conveying means includes
As the roller, it has an upper roller and a lower roller that rotate,
The sheet cutter according to any one of claims 1 to 3, wherein the sheet is sandwiched between an outer peripheral surface of the upper roller and an outer peripheral surface of the lower roller and conveyed backward. Sandwiching the sheet between the outer peripheral surfaces of each of the rotating first upper roller and the first lower roller and conveying the sheet backward;
The sheet that has passed through the first upper roller and the first lower roller is brought into contact with the outer peripheral surface of the rotating second roller and conveyed backward;
Cutting the sheet so that the width of the sheet becomes a predetermined width before the sheet that has passed through the first upper roller and the first lower roller passes through the second roller;
Controlling the tension of the sheet between the second conveying means and the first conveying means by controlling at least one of the rotational speed and torque of each roller;
The slit method characterized by including.

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