JPH01285556A - Sheet curl remedying device - Google Patents

Abstract

PURPOSE:To automatically and rapidly remedy a curl of a sheet with a high degree of accuracy by providing a control device for calculating an optimum embracing angle in accordance with a variation in the diameter of a roll to be wound up, and for controlling an embracing angle adjusting device in accordance with the result of the calculation. CONSTITUTION:An embracing angle adjusting device 34 controlled by a control device 16 displaces a decolor bar 31 from a position corresponding to a large web roll to a position corresponding to a small web roll in accordance with a variation in the diameter of a web roll 19 in such a condition that a main back-up roll 32 is set at a sheet push-in reference position. As a result, the embracing angle theta of a sheet 20 is adjusted between a small angle theta1 corresponding to the large web roll and a large angle theta2 corresponding to the small web roll. In this arrangement, the control device 16 successively calculates optimum embracing angles theta for corresponding to diameters of the web roll 19 (A, B, q are constants) and then controls the drive of a drive section 37 in the embracing angle adjusting device 34 in accordance with the result of the calculation in order to remedy a curl of a sheet 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet curl correction device for correcting curls in sheets such as plastic film, paper, and metal foil that are unwound from a take-up roll.

[Prior Art] For example, in a sheet cutting processing device, a sheet unwound from a take-up roll is cut into a predetermined length by a cutting machine. At this time 1
If the sheet unwound from the take-up roll is cut as it is, the cut sheet will curl. This curl is
This brings about inconveniences such as jamming within the sheet cutting line or jamming at the sheet introduction section when the sheet is later supplied to a printing machine or various devices.

Therefore, conventionally, as described in Japanese Patent Publication No. 80-48427, a decurling rubber is pressed between a pair of backup rolls onto a sheet unwound from a single take-up roll to give a hugging angle to the sheet, thereby correcting the curl of the sheet. A curl straightening device has been proposed.

Here, the amount of curl correction by the sheet curl correction device is determined by the holding angle of the sheet, and the larger the holding angle, the stronger the sheet is squeezed by the decurler rubber, and the larger the amount of curl correction.

On the other hand, when a sheet is unwound from a take-up roll, the degree of curl inherent in the sheet becomes stronger as the take-up roll diameter becomes smaller as unwinding progresses.

Therefore, when adopting the above-mentioned sheet curl straightening device, monitor changes in the take-up roll diameter and adjust the backup roll and decurling rubber so that the sheet holding angle increases as the take-up roll diameter becomes smaller. It is necessary to provide a holding angle adjustment device to adjust the relative position.

For example, the holding angle adjustment device changes the decal rubber from a position corresponding to a large take-up roll (small push position) to a position corresponding to a small roll according to a decrease in the diameter of the take-up roll, when the backup roll is set at the sheet pushing reference position. It is configured to be displaced toward position '#L (large push position).

Here, the sheet curl correction device described in Japanese Patent Publication No. 6G-48427 automatically adjusts the curl correction amount of the sheet according to the change in the take-up roll diameter. The optimal decal rubber drive amount for correction is digitally patterned with a chart. This chart is individualized for each type of sheet, structural specifications of the straightening device, etc., and each chart is based on experimental data collected in advance to determine the optimal decurler rubber drive amount as the take-up roll diameter changes over a certain width. It consists of:

[Problems to be Solved by the Invention] Incidentally, for example, in sheet cutting processing equipment in which a sheet curl straightening device is used, although there has recently been a strong desire for operational stability and high productivity, The reality is that the curl straightening device has become a bottleneck, and improvements in its operability have not been achieved. This is because the conventional control method, which controls the decal rubber drive amount using a digital pattern method, has the following problems that are difficult to solve.
The cause is that automation of curl correction cannot be achieved quickly and with high precision using a simple configuration.

■In order to improve curl correction accuracy, it is necessary to set an appropriate decurler rubber drive amount every time the take-up roll diameter changes minutely, which requires a huge amount of data. Therefore, a large number of man-hours are required for data collection.

■The above data is determined in advance for each type of sheet, structural specifications of the straightening device, etc. and stored in the data storage device, and the data suitable for the current straightening work is transmitted from the data storage device to the control device of the holding angle adjustment device. It is used as At this time, as described above, since the amount of data is enormous, it is necessary to secure a large storage capacity space in the data storage device and the control device, and it takes time to transmit data from the data storage device to the control device.

■The control operation of the decal rubber by the holding angle adjustment device becomes intermittent (step-like) in response to changes in the take-up roll diameter,
It is not possible to set the optimum holding angle for each take-up roll diameter, which changes from moment to moment.

An object of the present invention is to realize automation of curl correction quickly and with high precision using a simple configuration.

[Means for Solving the Problems 1] The present invention provides a sheet curling method that corrects curls of a sheet by pressing a decurrer rubber between a pair of backup rolls onto a sheet unwound from a take-up roll and giving a hugging angle θ to the sheet. In the straightening device, a holding angle adjustment device that adjusts the holding angle of the sheet by relatively displacing both the backup roll and the decal rubber, and a calculation formula [θ=A
/D1B] (where A, B, and q are predetermined constants), a control device that calculates the optimal holding angle according to a change in the diameter of the take-up roll, and controls the holding angle adjustment device based on the calculation result. It is made to have the following.

[Effect] The basis for establishing the present invention will be explained below.

(A) The sheet curl correction device corrects and improves curls imparted to the sheet on the take-up roll.

Therefore, the following is a consideration of curly curls. As shown in Fig. 6, for a sheet wrapped around a round bar (diameter H), when the sheet thickness is t and the wrapping angle is α, the neutral line length Lm, outer circumference length Lo, and inner circumference length Li of the wrapped sheet are , Lm=(H+t)α/2”(1)
Lo=(H+2t)α/2...(2)
The difference in elongation ΔL between the outer circumference and the inner circumference with respect to the neutral line, which is Li=Hα/2 (3), is ΔL=±tα/2 (0. Therefore, the strain electric current of the sheet is @ = Δl,
/ L m-±t/(H+t) ・(5
).

(B) According to the above equation (5), the original fabric strain @1 on the take-up roll (diameter D), which is the cause of curling, is ε2=±t/(Dot)...(6)
To correct this, the decal rubber (diameter d
), the correction strain ε2 is: ε2=±t/(d+t)...(7)
If the ratio of original fabric strain ε1 and straightening strain @2 is λ, then Input=εl/@2 = (d+t)/(Dot)...(
8) According to the empirical rule based on the inventor's experimental results, between the embrace angle 0 and the above entry, θ = 2

... (8), where the above (
In formula 9), t is a sufficient ratio compared to D, so t is removed from the denominator of input, and d and t are constant as long as the type of sheet and the structural specifications of the straightening device are determined, so The numerator is a constant component. As a result, θ=A/Dt+B−
(1G) holds true. Note that in (10), B is a constant for reinforcing the amount of curl correction, and in application, B=0 may be possible.

(C) As a result of further consideration of the exponent coefficient q in the above equation (10), as described below, q is 0.
It has been found that if any value in the range of 25 to 0.75 is selected, it is possible to always provide an appropriate θ for a wide range of changes in the diameter of the take-up roll.

That is, a test was conducted on the equation (10) in the range of qts from 0 to 2. The test used a decal rubber with a diameter of 12-1φ, the sheet material was white paperboard, and the basis weight was 270 ~
450 g/rn', sheet speed normally 300-330
m/win (maximum 380 m/win).

The test results, as shown in FIG. 5, are as shown in (1) to (2) below. In addition, it is preferable that the correct product curl after correction has a certain weak lower curl (chevron-shaped curl).
In the figure, curve a1 is the upper limit of allowable lower curl (strong curl), and curve b1 is the lower limit of allowable lower curl (weak curl).
, and the range between al and bl is the appropriate area.

■When q=0.75, A=2885.2,
B=8.94 and a curve b2 was obtained. b2 is the above b! at the intermediate roll diameter. deviates from. That is, q −0
, 75 or more, as shown by curve b3, the holding angle becomes too large (excessive correction effect) at a small roll diameter, and when the small roll diameter is adapted, the holding angle deviates at an intermediate roll diameter and becomes too small (correction effect too small). It is not possible to fit well into the roll diameter range. Therefore, it is preferable to set q = 0.75 as the practical upper limit of use.

■When q = 0.25, A = 21013,
B --5,313, and a2 curve was obtained. a2 deviates from the above al at the intermediate roll diameter. That is,
(If 1 = 0.25 or less, the holding angle becomes too small (correction effect is too small) at a small roll diameter as shown in curve a3, and if it is adapted at a small roll diameter, it deviates from at at an intermediate roll diameter and the holding angle becomes too large (correction effect). (excessive effect) and cannot be well adapted to the entire roll diameter range.Therefore, it is preferable to set q=0.25 as the practical lower limit of use.

■When q = 0.5, A snow 848.2, 8-
11.8, and a curve matching al was obtained. Also, q
! 0.5, A=718.8 and B=O, and a curve matching bl was obtained. Therefore, by setting q to 0.5, an extremely good curl straightening effect can be obtained over the entire roll diameter range.

In addition, in the above formula (10), q = 0.25 to 0.
75 (especially preferred is 0.5), and as a result of the test with A and B determined as described above, the basis weight of the sheet is 270 to 450 g.
Thickness change in the range (t-0, 35~0.58mm)
, a rate of change of 188%), it was also found that a single calculation formula could be used to adequately cope with this problem in practice without changing A and B. That is, A and B can be determined for each sheet type (material and thickness) group, and only a small amount of constant data for A and B is needed.

CD) In the implementation of the present invention, the holding angle adjusting device has the following relationship between the relative displacement S between the backup roll and the decurrer rubber and the holding angle θ: S=Kθ (11)
It is preferable that the structure be configured so that the following relationship is established.

As a specific example of this configuration, the relative movement locus of the decal rubber can be set perpendicularly to the straight line connecting both backup rolls.
It is to set it on the equal dividing line. The control device is the above (11)
) equation is used, the above S can be calculated extremely easily from θ calculated by the above-mentioned equation (lO), and the workability of the calculation can be improved.

According to the present invention established by the above (A) to (D), the following effects are achieved.

■ There are three constants, A, B, and q, prepared for each type of sheet, structural specifications of the straightening device, etc. (q is 0.25 to 0.75, more preferably q is fixed as 0.5) Then A, H
(2), and the amount of data to be collected or stored is extremely small.

■The above constant data is determined in advance for each type of sheet and the configuration specifications of the straightening device and stored in the data storage device, and the data suitable for the current straightening work is transmitted from the data storage device to the control device of the holding angle adjustment device. and used. At this time, as mentioned above, since the amount of data is small, the storage capacity space of the data storage device and control device is extremely small.
The data transmission time from the data storage device to the control device can also be shortened to a negligible extent.

■Also, the calculation processing speed of the calculation formula is, for example, several ion seconds, and it can be considered as completely continuous operation control for changes in the winding roll diameter, so the optimal holding angle can be determined for each winding roll diameter that changes from moment to moment. Can be set. Therefore, the sheet conveyance posture at high speeds can be controlled more accurately, and it is possible to provide not only stable operation at high speeds but also additional benefits such as a reduction in paper dust and an improved stacking appearance.

[Example] Fig. 1 is a schematic diagram showing a sheet cutting processing device as an example to which the present invention is applied, Fig. 2 is a schematic diagram showing an embodiment of a sheet curl correction device, and Fig. 3 is a schematic diagram showing an embodiment of a sheet curl correction device. FIG. 4 is a schematic diagram showing the operation of the sheet curl correction device. FIG. 5 is a diagram showing an example of test results using the calculation formula of the present invention. FIG. 6 is a diagram showing the curl of the sheet. FIG. 2 is a schematic diagram showing the generation mechanism.

The sheet cutting device 10 includes a sheet supply device 11, a sheet joining device 12, a curl correction device 13, a feed roll 14, a cutter 15, and a control file.

The sheet supply device 3111 supports the original fabric rolls 19 (old fabric roll 19A and new fabric roll 19B) at both ends of the rotating arm 18 supported by the pedestal 17, and feeds the sheets 20 from the original fabric rolls 19. Unwind and supply.

The sheet joining device 112 includes a pressing roller 21 and a knife 2.
2, when unwinding the sheet 20 continuously from the original roll 19,
The end side of the sheet 9A is pressed against the double-sided tape attached to the start side of the sheet of the new roll 19B, and both sheet parts are joined.
Separate the final end part of A on the terminal side from the above joint part.

The curl correction device H13 performs curl correction of the sheet 20 in response to changes in the diameter of the original fabric roll 19, as will be described in detail later.

The feed roll 14 applies tension to the sheet 20 to unwind the sheet 20 from the raw roll 19 .

The cutting fi15 cuts the sheet 20, which has been straightened by the curl straightening device 13 and is continuously running, into an appropriate length.

The control device 16 includes the sheet supply device 3111, the sheet joining device 12, the curl correction device 13, and the feed roll 14.
, and control each of the cutting machines 15.

At this time, the control device M16 counts the rotational speed Nl of the old web roll 19A using the web rotation detector 16A provided on the swing arm 18 in order to monitor the change in the diameter of the old web roll 19A. Intermediate roll 16B (diameter E is known) by rotation detector 16c of intermediate roll 16B
The rotational speed N2 of is counted. The control device 16 controls the sheet speed V=πDNl=πEN2 f) Related color, CP
At U, o=E(N2/Nl) is always calculated, and the diameter of the old original fabric roll 19A is always bundled.

In addition, when the diameter of the old material roll 19A decreases to the replacement preparation diameter F, the control device W16 controls the sheet feeding device! t1
1, the old original fabric roll 19A is positioned at the joining work position shown in FIG.
The sheets of A and the new roll 19B are joined together.

The specific configuration of the curl correction device 13 will be described below.

The curl straightening device 113 includes a decal rubber 31 , a pair of main backup rolls 32 provided on both sides of the decal rubber 31 , a pair of sub backup rolls 33 provided on both sides of the main backup roll 32 , and a holding angle adjustment device for driving the decal rubber 31 . N34, the main backup roll 32 is provided with a sudden change in angle device 35 for driving the main backup roll 32.

That is, the curl correction device 13 presses the decurler rubber 31 between a pair of main backup rolls 32 against the sheet 20 unwound from the original fabric roll 19, and applies a hugging angle θ to the sheet 20 to correct the curl of the sheet 20. to correct.

■The holding angle adjustment device 34 is operated by a drive section 37 controlled by the control device ff11B, for example, a screw type feed device 3.
8, the decal rubber 31 is driven.

The decal rubber 31 is attached to the left and right main backup rolls 32.
It can be displaced up and down on the perpendicular bisector of the straight line connecting the .

That is, the holding angle adjusting device 134 controlled by the control device 16 moves the decurrer rubber 31 to the original fabric roll 19 under the condition that (1) the main backup roll 32 is set at the sheet pushing reference position N (solid line position in FIG. 2); According to the change in the diameter of the sheet 20, the sheet 20 is displaced from the position corresponding to the large fabric roll (the position indicated by the two-dot chain line in FIG. 2) to the position corresponding to the small fabric roll (the position N shown in solid line in FIG. 2), and as a result, the holding angle of the sheet 20 is changed. Adjust θ between the small angle θl corresponding to the large fabric roll and the large angle θ2 corresponding to the small fabric roll (see FIG. 3). At this time, the control device 16 adjusts the The optimal holding angle θ (or decal rubber 31
The amount of displacement S) of the decal rubber 31 can be determined sequentially using the calculation formula described later, and the optimal holding angle θ (or the optimal amount of displacement S of the decal rubber 31) is determined corresponding to the diameter calculated as described above. The drive unit 37 is controlled so that the following is achieved.

Here, the control device 16 adjusts the optimal holding angle θ (or decurrer rubber 31
When calculating the amount of displacement S), the calculation formula [θ=A/D'
+B] or [S=Kθ]. Here, constant A,
The data B and q are determined in advance for each type of sheet 20 and the structural specifications of the straightening device, and are stored in the data storage device 110.
The data of A, B, and q, which are stored in 0 and are suitable for the current correction, are supplied to the control device 16 from the data storage device lOO. In addition, it is preferable that each of the above-mentioned 94 lines is <0.25 to o, 75, and particularly preferably 0.5.

Further, the holding angle adjustment device 34 controlled by the control device 16 is controlled by the control device 1B as described above.
2 to perform sheet joining between the old original roll 19A and the new original roll 19B, the decurrer rubber 31
from the position corresponding to the small roll to the position corresponding to the large roll.

(2) The hugging angle sudden change device 35 drives the main backup roll 32 using, for example, a cylinder 40 operated by a drive section 39 controlled by the control device 16.

That is, the holding angle sudden change device 35 controlled by the control device 16 causes the control device 3116 to change the holding angle adjusting device 34 as described above to move the decurler/<-31 from the position corresponding to the small fabric roll to the position corresponding to the large fabric roll. When the return is started, the main/pickup roll 32 is retracted from the sheet pushing reference position in the non-pushing (or pushing-relaxing) direction at a timing between the two paths, and the holding angle θ of the sheet 20 is suddenly changed.

■As described above, the sub backup rolls 33 are fixedly set in advance on both sides of the decurling rubber 31 and the main backup roll 32, and when the holding angle sudden change device 35 retracts the main backup roll 32 from the sheet pushing reference position, the The sheet 20 is guided so that the holding angle 0 of the sheet 20 becomes a value (θ1) that matches the diameter of the large-diameter new roll 19B.

Next, the operation of the above embodiment will be explained.

The curl straightening device 13 operates as follows.

(A) When unwinding sheets from the same material roll 19, the holding angle adjustment device 34 functions, and the main backup roll 3
2 is set at the sheet pushing reference position, by displacing the decal rubber from the position corresponding to the large fabric roll to the position corresponding to the small fabric roll according to the change in the diameter of the fabric roll, the holding angle of the sheet 20 can be adjusted. θ is set to the optimum state for the current roll diameter, and as a result, the curl is appropriately corrected (see FIG. 4(A)).

(B) New and old original rolls 19A produced by sheet joining device 12
, 19B, according to the following (■) to (■).

(2) The holding angle adjustment device 34 starts returning the decurrer rubber 31 from the position corresponding to the small original roll to the position corresponding to the large original roll.

■ At the start of the return operation described in (■) above and at the timing, the holding angle sudden change device 35 retracts the main backup roll 32 from the sheet pushing reference position in the non-pushing (or pushing relaxation) direction to adjust the holding angle of the sheet 20 to 0. make a sudden change. At this time,
The sheet 20 is guided by the sub-backup roll 33, and the holding angle θ of the sheet 20 is instantaneously switched and set to match the diameter of the new large-diameter roll 19B, and as a result, the sheet 20 is unwound from the large-diameter new roll 19B. (see Figure 4 CB))
.

In addition, the holding angle sudden change device 35 is the main backup roll 3.
Since it is sufficient to selectively switch the seat 2 to two positions, the seat pushing reference position and the retracted position, it is easy to complete the switching operation instantaneously.

■Holding angle adjustment @@34 completes returning the decurrer rubber 31 to the position corresponding to the original fabric roll (see Fig. 4(C)).

(2) The sudden holding angle changing device 35 resets the main backup roll 32 from the retracted position (2) above to the sheet pushing reference position (see FIG. 4 CD).

(C) As in (A) above, new fabric roll 19
Depending on the decrease in the roll diameter of B, the holding angle adjustment device 34
The decurler rubber 31 is displaced from the position corresponding to the large fabric roll to the position corresponding to the small fabric roll, and the holding angle of the sheet 20 is set to the optimum state for the current fabric roll diameter, resulting in appropriate curl correction. (Figure 4 (
(See E) and (F)).

Therefore, according to the above embodiment, when changing over the old and new rolls in the above (B), the sheet cutting processing device! ! 10
While maintaining the line speed at a high speed determined by the processing capacity of the cutting machine 15, for example, the holding angle of the sheet 20 can be changed instantaneously following a sudden change in the diameter of the material roll. Therefore, the curl of the sheet 20 can be reliably corrected to an appropriate state while maintaining the productivity of the line.

In addition, in FIG. 4, (A), CF) is the raw roll 1
9, the decurrer rubber 31 is at the position corresponding to the small roll, and the holding angle 0 of the sheet 20 is the maximum value θ2.
It is. In addition, (C) is when the diameter of the original fabric roll 19 is at its maximum, and the decurrer rubber 31 is in a position corresponding to the large original fabric roll.
The embrace angle θ of C) 20 is the minimum value θl.

In addition, in FIG. 4, the hugging angle θ of the sheet 20 is (
There are slight variations in each of B), (C), and (D), but
If the installation interval of the sub-backup rolls 33 is set sufficiently larger than the installation interval K of the main backup rolls 32,
The variation in the embrace angle θ is minute and can be ignored in practical terms.

Furthermore, in the above embodiment, since the calculation formulas for θ and S as described above are used in the control device 16, the following effects are achieved.

■There are three constants, A, B, and q, prepared for each type of sheet, structural specifications of the straightening device, etc. (q -0, 25 to 0.75,
More preferably, if q is fixed as q = 0.5, A
, B), and the amount of data to be collected or stored is extremely small.

■The above constant data is determined in advance for each type of sheet and the configuration specifications of the straightening device and stored in the data storage device, and the data suitable for the current straightening work is transmitted from the data storage device to the control device of the holding angle adjustment device. and used. At this time, as described above, since the amount of data is small, the storage tα capacity space of the data storage device and the control device is extremely small, and the data transmission time from the data storage device to the control device can be shortened to a negligible extent.

■Also, the calculation processing speed of the calculation formula is, for example, several tens of milliseconds, and it can be considered as completely continuous operation control for changes in the winding roll diameter, so the optimal holding angle can be determined for each winding roll diameter that changes from moment to moment. Can be set. Therefore, the sheet conveyance posture at high speeds can be controlled more accurately, and it is possible to provide not only stable operation at high speeds but also additional benefits such as a reduction in paper dust and an improved stacking appearance.

Furthermore, in one embodiment of the present invention, the holding angle adjusting device adjusts the holding angle by controlling the displacement of the main backup roll in accordance with changes in the diameter of the take-up roll, instead of controlling the displacement of the decal rubber. At this time, the hugging angle sudden change device instantaneously switches the side of the decal rubber between the sheet pushing reference position and the retracted position.

Furthermore, in carrying out the present invention, the holding angle adjusting device is not limited to displacing the other of the main backup roll and decal rubber in a straight line, but may also displace the other in a curved manner by a turning operation or the like. .

[Effects of the Invention] As described above, according to the present invention, automation of curl correction can be realized quickly and with high precision with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a sheet cutting device as an example to which the present invention is applied, FIG. 2 is a schematic diagram showing an embodiment of the sheet curl correction device, and FIG. 3 is a diagram showing changes in the sheet holding angle. A schematic diagram, FIG. 4 is a schematic diagram showing the operation of the sheet curl correction device, FIG. 5 is a diagram showing an example of test results based on the calculation formula of the present invention, and FIG. 6 is a diagram showing the sheet curl generation mechanism. It is a schematic diagram. 13... Curl correction device, 16... Control device. 19... Original fabric roll (take-up roll). 20...Sheet, 31...Decal rubber, 32...Main backup roll (backup roll), 34...Holding angle adjustment device. Agent Patent Attorney Osamu Shiokawa Figure 4

Claims (3)

[Claims] (1) In a sheet curl correction device that corrects the curl of a sheet by pressing a decurrer rubber between a pair of backup rolls onto a sheet unwound from a take-up roll and giving the sheet a holding angle θ, both the backup roll and the decurrer rubber are used. A holding angle adjustment device that adjusts the holding angle of the sheet by relatively displacing the sheet, and a calculation formula [θ = A/D
^q+B] (where A, B, and q are constants determined in advance), calculates the optimal holding angle according to changes in the take-up roll diameter, and controls the holding angle adjustment device based on the calculation result. A sheet curl correction device characterized by comprising: (2) The sheet curl correction device according to claim 1, wherein the constant q of the calculation formula is 0.25 to 0.75. (3) The holding angle adjusting device is configured such that a relationship [S=Kθ] is established between the relative displacement amount S between the backup roll and the decurler rubber and the holding angle θ. The sheet curl correction device according to claim 1 or 2.