JPH0733198B2 - Web winding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a web winding method, and more particularly, to determine an optimum web winding tension pattern and wind the web around a winding core according to the winding tension pattern. The present invention relates to a method for winding a web to be taken.

[Conventional technology]

Conventionally, when winding a web such as a plastic film or a metal foil around a winding core, the winding tension is empirically determined, and the main tension pattern of the winding tension decreases with the increase of the winding diameter. Taper tension, constant constant tension regardless of winding diameter, reverse taper tension increasing with increasing winding diameter, and the like.

Further, when a sufficient winding hardness cannot be obtained only by these tension patterns, it has been widely practiced to bring a rubber roller called a touch roll or a reion roll into contact with a take-up roll for winding.

On the other hand, JP-A-60-242160 discloses a method of controlling the tension applied to the web during winding so that the circumferential residual stress of each layer of the wound coil is substantially constant.

[Problems to be solved by the invention]

However, when winding a web with taper tension or constant tension, wrinkles are likely to occur near the core, radial stress near the core is likely to be large, and dust or other foreign matter may enter between the webs. There is a problem that the web is deformed and becomes a transfer to the web, which tends to result in a defective product. Also, when using a touch roll, it has the effect of preventing wrinkles and axial deviation of the take-up roll.However, when taking up a web with a weak surface, there is a problem of surface scratches due to foreign matter and transfer of foreign matter. There is. These problems are particularly noticeable when winding at high speed. Further, the method of winding a web described in JP-A-60-242160 does not consider the influence of an air film interposed between the webs when calculating the circumferential residual stress of the web, and It was insufficient as an accurate and fine control.

The present invention has been made in view of the above circumstances, and does not cause wrinkles in the roll, does not damage the web surface by the radial pressure, and does not cause axial misalignment of the roll. The purpose is to provide a method.

[Means for solving problems]

In order to achieve the above object, the present invention determines the radial stress at an arbitrary web winding radius when a web is wound with a certain winding tension pattern with the web winding radius as a parameter. , Young's modulus in radial direction,
A radial stress at each web winding radius thus obtained based on the winding tension pattern or the like, or a lateral deviation resistance force obtained based on this radial stress is set in advance based on the web winding radius. Within the appropriate range, the certain take-up tension pattern is determined as a desired take-up tension pattern, and the actual web take-up tension at the time of taking up the web is set to the current web in the decided take-up tension pattern. A method for winding a web in which a web is wound around a winding core by controlling a winding tension corresponding to a winding radius, wherein a radial stress at an arbitrary web winding radius is obtained. , An air film interposed between the web and the web
The average Young's modulus of the layer structure is obtained, and this Young's modulus is used as the equivalent Young's modulus of the radial direction Young's modulus.

[Action]

According to the present invention, the Young's modulus in the radial direction is calculated in consideration of the influence of the air film interposed between the webs, and the Young's modulus in the radial direction is used to calculate the stress in the radial direction at each web winding radius. A radial stress close to the stress can be obtained. Therefore, each of the radial stresses thus obtained or the lateral deviation resistance force obtained based on the radial stresses is within a proper range preset based on the web winding radius. The winding tension pattern) can be determined. Then, by controlling the actual winding tension of the web at the time of winding the web so as to have the optimum winding tension pattern, it is possible to perform good winding in the web winding radial direction.

〔Example〕

Hereinafter, preferred embodiments of a web winding method according to the present invention will be described in detail with reference to the accompanying drawings.

First, the present invention will be described in principle.

The take-up roll may laterally shift during conveyance due to an external force in the lateral direction. The lateral deviation resistance force Fr at the radius r position against such lateral deviation is expressed by the following equation.

Fr = μr × Ar × σr (1) where μr: friction coefficient, Ar: web surface area at radius r, σr: radial stress in roll The radial stress σr in the roll is Altman (Altm
ann) is derived as follows.

Et: Young's modulus in the circumferential direction, Ec: Young's modulus of the core Er: Young's modulus in the radial direction, T: Winding tension r: Any web winding radius, R: Roll outer radius νt: Circumferential Poisson's ratio νr: Radial Poisson's ratio The above equation (2) has been widely used for winding stress analysis, but the logical value and actual measurement of the radial stress σr obtained by this equation (2) are largely different. However, the conventional winding tension pattern has been empirically determined as described above.

In the present invention, attention is paid to the fact that the radial stress in the actual take-up roll is affected by the air film interposed between the webs, correction is made in accordance with this air film, and is obtained by the above equation (2). The radial stress σr was made to match the measured value well.

Then, the radial stress σr obtained by the equation (2)
However, as shown in FIG. 2, the winding tension pattern was determined so as to fall within an appropriate range in the radial direction in the winding roll, and the actual winding tension was controlled according to this winding tension pattern. Here, the appropriate range is an upper limit value σrmax at which no web movement occurs.
And the lower limit value σrmin where the base shift and wrinkle do not occur are set. The upper limit value σrmax and the lower limit value σrmin can be determined in advance by an offline test.

Now, in the formula (2), the air film (thickness of the air film) interposed between the webs has the greatest influence on the Young's modulus in the radial direction. Therefore, the equivalent Young's modulus considering the influence of the air film thickness was introduced as follows.

As shown in FIG. 3, the take-up web is composed of a web and an air film.
It is considered that they have a layered structure, and the Young's modulus Er (hereinafter referred to as the equivalent Young's modulus) that averages these is expressed by the following equation.

However, E1: Young's modulus of the web, E2: Young's modulus of the air film, h:
Average thickness of air trapped between webs, t: thickness of web In the above equation (3), Young's modulus E2 of the air film and air film thickness h are unknown, but due to the axial symmetry of the phenomenon, If the air film thickness changes only in the radial direction and is subject to isothermal changes, the Young's modulus E2 of the air film can be treated as equivalent to the radial stress σr. That is, E2≈σr (4) On the other hand, the air film thickness h is theoretically difficult to obtain, and in the present invention, the air film thickness h is obtained from the following empirical formula.

FIG. 4 is a flowchart showing a procedure for deriving an empirical formula for obtaining the air film thickness h. As shown in the figure,
First, the winding conditions (winding speed V, winding tension T) are set (step 10), and the radial stress σr ′ at each winding radius is approximated by the least squares method (step 12),
The approximated value is taken as Young's modulus E2 of the air film as shown in the equation (4) (step 13).

Next, assuming the air film thickness h (step 14), the equivalent Young's modulus Er is calculated based on the equation (3) (step 14).
15), using the calculated equivalent Young's modulus Er, calculate the radial stress σr according to the equation (2) (step
16). Then, in step 17, the measured value σr ′ and the calculated value σr
r is compared, the air film thickness h is corrected until they match, and steps 14 to 17 are repeated, and the air film thickness h when they match is adopted.

FIG. 5 shows the core radius Rc = 48.5 mm according to the procedure shown in FIG.
The stress σr and the air film thickness h obtained under the conditions of web width b = 180 mm, V = 100 m / min and T = 22 kg / m are shown. From this figure, it can be seen that the air film thickness h interposed between the webs can be regarded as substantially constant in the radial direction.

Then, the winding tension T and the winding speed V are changed to obtain the air film thickness h by the above-mentioned method, and the empirical formula h (V, T) shown in the following formula is obtained from these relationships (step 18).

However, K: proportional constant, α, β: constant determined by web width and rigidity Under the above conditions, K = 0.777, α = 0.857, β = 1.11.
Became.

Further, FIG. 6 shows the air film thickness h in the case where the winding tension V varies (= 100 m / min) under the same conditions and the winding tension T changes. Similarly, FIG. 7 shows the winding tension. T (= 22kg /
The air film thickness h in the case where the winding speed V changes while m) is kept constant is shown.

Next, a method for determining the optimum winding tension pattern based on the above equations will be described in detail with reference to the flowcharts shown in FIGS. 8 and 9.

As shown in FIG. 8, first, a take-up tension pattern having parameters of the take-up speed V of the web and the take-up radius of the web is assumed, and the take-up speed V and the take-up tension T at each take-up radius are set to (5). The air film thickness h is calculated by substituting it into the equation (step 20). The web is usually wound at a constant winding speed. Therefore, as the winding speed V, the winding speed at which the web is actually wound is used. Further, the air film thickness h is obtained for each winding radius, but for simplification, a certain winding radius will be described below.

Next, Young's modulus E2 of the air film interposed between the webs, which is generated when the web is wound up to the end with the winding tension pattern, is obtained (step 21). The Young's modulus E2 of this air film is obtained by the procedure shown in FIG.

That is, as shown in FIG. 9, the Young's modulus E2 of the air film is first assumed (step 30), and the Young's modulus E2 and the air film thickness h calculated in step 20 of FIG. The equivalent Young's modulus Er is calculated by the formula (3) (step 31), and the radial stress σr is calculated by the formula (2) using the calculated equivalent Young's modulus Er (step 32). Then, in step 33, the assumed Young's modulus E2 and the calculated radial stress σ
r is compared, and Young's modulus E2 is corrected until both agree, and steps 30 to 33 are repeated, and the Young's modulus E2 at the time of agreement is calculated as described in equation (4). (Step 34).

In this way, when the thickness h of the air film and Young's modulus E2 are obtained in steps 21 and 21 (Fig. 8), the radial equivalent Young's modulus Er of the web is calculated based on these equations (3). Yes (step 22). Then, the calculated equivalent Young's modulus Er is substituted into the equation (2) to calculate the radial stress σr (step 23).

The radial stress σr obtained by the above calculation is for a certain winding radius as described above, but the air film thickness h, the Young's modulus E2 of the air film, the radial equivalent Young's modulus Er of the web and the radial direction The stress σr is calculated for each winding radius in the same manner as described above.

In step 24, it is judged whether or not the radial stress σr calculated for each winding radius as described above is entirely within an appropriate range set in advance at the corresponding winding radius (see FIG. 2). If it does not fall within the range, the assumed winding tension pattern is appropriately modified, and steps 20 to 24 are repeated until it falls within the proper range.

When the radial stress σr falls within the proper range over the entire winding radius, the winding tension pattern assumed at that time is determined as the optimum winding tension pattern (step 25).

Next, a web winding device for taking the web on the film core according to the determined winding tension pattern will be described.

In FIG. 1, this web winding device controls a rotation speed of a winding shaft to roll a web W at a predetermined winding speed through a roller 40, a tension roller 42, and rollers 44 and 46. I'm trying to wind it up. On the other hand, the winding tension of the web W during the winding is adjusted by the winding tension control section shown below.

The winding tension control section gives a signal to the web W based on a signal from the signal generating section 50 that generates a signal indicating the target winding tension and the signal from the signal generating section 50. It is composed of an actuator unit 60.

The signal generator 50 includes a winding speed detector 52, an angular velocity detector 54,
Winding radius calculator 56 and winding tension pattern generator 58
The winding speed detector 52 detects the winding speed V of the web W based on the rotation of the roller 46, and outputs a signal indicating the detected winding speed V to the winding radius calculator 56. The angular velocity detector 54 detects the angular velocity ω of the winding shaft, and outputs a signal indicating the detected angular velocity ω to the winding radius calculator 56. The winding radius calculator 56 calculates the winding radius r of the web W based on the above two input signals by the following equation, r = V / ω (6), and outputs a signal indicating the winding radius r to the winding tension. Output to the pattern generator 58.

The winding tension pattern generator 58 stores the optimum winding tension pattern obtained by the procedure shown in FIG. 8, and based on the signal indicating the winding radius r added from the winding radius calculator 56, The winding tension at the winding radius indicated by the signal is read from the winding tension pattern, and the signal indicating the winding tension is output to the actuator unit.
Output to the pressure control valve 66 of 60.

The actuator unit 60 includes a movable arm 62 having a tension roller 42 at one end, an air cylinder 64, a pressure control valve 66, and an air pressure source 68. The pressure control valve 66 supplies high pressure air applied from the air pressure source 68. The pressure air corresponding to the signal indicating the winding tension is adjusted, and the adjusted pressure air is added to the air cylinder 64. The air cylinder 64 has a pressure control valve 66
The force corresponding to the pressure air applied from the movable arm 62 is applied to the movable arm 62, and the required force (the winding tension indicated by the signal output from the winding tension pattern generator 58 is applied to the tension roller 42 via the movable arm 62. The force required to apply to W) is applied to adjust the winding tension of the web W.

In this manner, the web W is wound around the winding core 48 by the winding tension pattern generator 58 in accordance with the optimum winding tension pattern stored in advance.

In the present implementation order, the optimum winding tension pattern is determined so that the radial stress σr calculated based on the formula (2) falls within an appropriate range, but the invention is not limited to this.
From the radial stress σr, the lateral deviation resistance force Fr at each winding radius is further calculated based on the equation (1), and the lateral deviation resistance force Fr is calculated.
The optimum winding tension pattern may be determined so that Fr falls within an appropriate range in which a preset lateral deviation phenomenon or wrinkle does not occur.

〔The invention's effect〕

As described above, according to the web winding method of the present invention, by introducing the radial equivalent Young's modulus in consideration of the air winding thickness interposed between the webs, the radial stress that is in good agreement with the practical value is obtained. Can be calculated by a theoretical formula, and as a result, the optimum winding tension pattern can be determined so that the radial stress or the lateral shift resistance becomes a desired value over the winding radius. Thus, suitable web winding can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a web winding device to which the method of the present invention is applied, and FIG. 2 is an example of an appropriate range of radial stress used when determining a winding tension pattern according to the present invention. FIG. 3, FIG. 3 is a view conceptually showing a two-layer structure of an air film and a web, and FIG. 4 is a flow chart showing a procedure for deriving an empirical formula for obtaining the air film thickness between the webs. The figure is a graph showing changes in the radial stress and the air film thickness with respect to the winding radius obtained according to the procedure of FIG.
FIG. 6 is a graph showing the relationship between the winding tension and the air film thickness, FIG. 7 is a graph showing the relationship between the winding speed and the air film thickness, and FIG. 8 is the determination of the winding tension pattern according to the present invention. FIG. 9 is a flow chart showing a procedure for doing so, and FIG. 9 is a flow chart showing a procedure for determining the Young's modulus of the air film. 42 …… tension roller, 48 …… winding core, 50 …… signal generator, 52 …… winding speed detector, 54 …… angular velocity detector, 56…
... Winding radius calculator, 58 ... Winding tension pattern generator, 60 ... Actuator part, 62 ... Movable arm, 64 ...
… Air cylinder, 66… Pressure control valve, 68… Air pressure source.

Front page continued (72) Inventor Toshiyuki Ishiguro, 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture, Fuji Photo Film Co., Ltd. (72) Inventor, Yasuyuki Hara, 200, Onakazato, Fujinomiya City, Shizuoka Prefecture Fuji Photo Film, Inc.

Claims (5)

[Claims] 1. A radial stress at an arbitrary web winding radius, which occurs when a web is wound with a certain winding tension pattern having a web winding radius as a parameter, is defined as a web winding radius, a radial Young's modulus, The radial stress at each web winding radius thus obtained based on the winding tension pattern or the like, or the lateral deviation resistance force obtained based on the radial stress is set in advance based on the web winding radius. Within the appropriate range, the certain winding tension pattern is determined as a desired winding tension pattern, and the actual web winding tension at the time of winding the web is set to the current web tension in the determined winding tension pattern. Take-up of the web by controlling the take-up tension corresponding to the take-up radius to take up the web on the core Method, when determining the radial stress at the arbitrary web winding radius, the average Young's modulus of a two-layer structure of the air film and the web interposed between the webs is determined, and the Young's modulus is measured in the radial direction. A method of winding a web characterized in that it is used as an equivalent Young's modulus of Young's modulus. 2. The following equation derived by Altmann, which is the radial stress at any web winding radius: Et: Young's modulus in the circumferential direction, Ec: Young's modulus of the core Er: Young's modulus in the radial direction, T: Winding tension r: Any web winding radius, R: Roll outer radius νt: Circumferential Poisson's ratio νr: The method for winding a web according to claim (1), which is obtained by a Poisson's ratio in the radial direction. 3. The equivalent Young's modulus is expressed by the following equation: However, E1: Young's modulus of web, E2: Young's modulus of air, t: thickness of web, h: average thickness of air trapped between the webs. The web according to claim (1). Winding method. 4. The average thickness h of the air is expressed by the following equation: However, K: proportional constant, α, β: constant determined by web width and rigidity, V: winding speed, T: winding method according to claim (3). 5. The Young's modulus E2 of the air is assumed to be an arbitrary value, the equivalent Young's modulus is calculated based on this value, and the radial stress and the radial stress obtained by using the calculated equivalent Young's modulus are calculated. When the assumed value agrees with the assumed value, the assumed value is taken as the Young's modulus of air.
A method for winding a web according to the item.