MXPA99011175A - Uniformly wound rolls of soft tissue sheets having high bulk - Google Patents

Abstract

A uniformly wound parent roll of soft, high bulk tissue has greater uniformity in sheet basis weight, machine direction stretch and bulk when compared to parent rolls wound by conventional winding methods. The method involves carrying the tissue sheet on a relatively air impermeable transfer belt (18) which traverses an unsupported span between two winding drums. The sheet (15) is transferred from the transfer belt to the parent roll (25) as the parent roll is urged against the sheet/transfer belt at a point within the unsupported span. The resulting deflection of the transfer belt is detected and, in response, the reel spool position is controllably changed to maintain the deflection within predetermined limits. The tension of the sheet is controlled by the predetermined differential speed between the outer most surface of the parent roll and the transfer belt.

Description

ROLLOS OF TISU SHEETS SOFTLY ROLLED UNIFORMLY WHICH HAVE DN VOLUME HIGH Background of the Invention In the manufacture of various types of tissue products such as facial tissue, bathroom tissue, paper towel and the like, the dried tissue tissue or the sheet coming out of the tissue machine is initially wrapped in a padr and temporarily it is stored for further processing. Some time later, the parent roll is unrolled and the sheet has become a form of final product.

In the wrapping, of the tissue of a large parent roll, it is vital that the roll is wound in a manner which avoids main effects in the roll and which allows an efficient conversion in the final product, since whether it is placed in facial tissue sheet boxes, tissue rolls for bathroom, rolls of engraved paper towels, and the like Ideally, the parent roll has a cylindrical shape essentially, with a smooth cylindrical surface and surfaces of parallel and smooth flat ends. The cylindrical main surface and the end surfaces must be free of waves, humps, ripples, eccentricity, wrinkles etc., or in other words, the roll must be "dimensionally correct". Similarly, the shape of the roll should be set so that it does not depart from its cylindrical shape during storage or handling routine, or in other words, the roll should be "dimensionally stable". Defects can force the entire rolls to be scraped if they have become unsuitable for high speed conversion.

Many defects can be introduced by improper rolling, especially when winding soft tissue tissues easily compressible high volume. A large number of such defects are discussed and shown in the photographs, in an article by W.J. Guilmore, "Support for Rollover Defect Terminology" TAPPI CA 1228; Proc. 197 Tappi Terminator Conference in Atlanta, Georgia 1973, page 5-19. Inadequate tissue tension near the core of the roll can cause the outer regions of the roll to compress and roll inward, leading to a bulge in a star pattern, commonly called "star burn" as described by James K. Good, " The Science of Rolling Rolls, "Product to Make Paper, transcript of the Oxford Fundamental Research Symposium, September 1973, CF Baker edition volume 2, Pira International, Leatherhead, England, 1993 pages 855-881. In addition, crashing causes the release of tissue tension around the core which normally provides sufficient friction between the core and adjacent layers of tissue. This friction wall can result in a slip of the core or telescope where the majority of the roll (except for a few layers around the core and a few layers around the core around the outermost regions) moves en masse to one side with respect to the roll axis, making the roll unusable.

The hard pressure point drum reels commercially available today from the type with impeller aided in the center, are described by T. Svandquist, "Designing a Reel for Soft Tissue" 1991, The tissue manufacturing seminar by Karlstad, Sweden, have been successfully used for rolling rolls of compressible tissue fabrics having volume d up to about 8 to 10 cubic centimeters per gram, while avoiding the winding problems mentioned above by reducing the pressure point force and It relies mainly on the control of tissue tension through the modulation of the impulse aided in the center for the d axis. However, when such method is used for winding tissue sheets having high volume, such as those having a volume of about 9 cubic centimeters or more and a high level of softness, as characterized, for example, By a maximum inclination in the machine direction of about 10 kilograms or less po 3 inches in width of sample, these problems recur. These winding problems are accentuated when trying to roll large rolls with diameters from about 7 inches to about 150 inches or larger, particularly at high speeds.

Without wishing to be bound by a theory, it is believed that when a fabric is put into a pressure point formed between the parent roll and a pressure roll, two principal factors besides the incoming tissue tension affect the final stresses within the roll. rolled First, the part of the parent roll at the pressure point is deformed to a radius, which is smaller than the undistorted radius of the parent roll. The expansion of the parent coil from its deformed radius to its deformed radius stretches the tissue and results in a more substantial internal stress increase of the established tension of the fabric going into the pressure point. Otrcr -factor is a.sometimes called the "secondary winding" effect. A part of the fabric is added to the roll after it passes first through the pressure point between the parent roll and the pressure roll. This then passes under the pressure point repeatedly at each rotation of the parent roll, while more layers are added to the outside diameter. As each point near the surface of the roll re-enters the pressure point, the fabric is compressed under the pressure of the clamping point d, causing the air in the hollow volume of the fabric to be expelled between the layers. It can reduce the friction between the layers sufficiently to allow the layers to slip tightly around the inner layers as described by Erickkson et al., "Deformations in the Rolls of Paper" page 56-61 and Le ke and others, Factors Involved In Rolls Large Diameter Newspaper Rolls on a Do Drums Reel, page 79-87 International Conference Process for Rolling Technology 1987. The tension in each roll when added to the parent roll causes a compression force exerted by each outer layer to the layers below, therefore, the cumulative effect of compression of the outer layers will normally cause that tissue in the region around the core to have a higher interlayer pressure. The secondary winding also adds to this pressure. Soft tissue is known to yield when subjected to compression, thus absorbing some of the pressure increases to the extent that it loses its capacity to deform. Consequently, the accumulative pressure can rise at a steep rate to excessive levels that can cause a variation of width in the unrolling properties of the parent rolls.

Unfortunately, the internal pressure and tissue tension gradient has along the radius of a conventionally wound parent roll, even when successful and avoids problems of dimensional stability, leads to undesired variability in the properties of the fabric. The high tension in some regions causes some of the stretch in the direction of the machine to be pulled out during rolling, and high internal pressures result in loss of volume. Upon unwinding, regions that have been stretched further by high tension at and after the point of pressure will have a lower basis weight due to the longitudinal stretch of tissue. These changes in the properties of cruciale tissue lead to the variability of product quality and difficulties in conversion operations.

The compensation for internal pressure build-up, according to the above-mentioned method described by T Svandquist, can be carried out only to a certain extent. By reducing the density and strength of the woven material many lower than the levels mentioned, the inserts The magnitude of the frictional forces of other factors which change during the course of lightning makes a precise pressure point load control difficult. Alternatively, loss of control of the winding process may result in an investment in the voltage gradient which can lead to crashing and core slipping problems as described above.

If it was no longer necessary to use a hard pressure point on the tissue backing, many of these problems could be avoided and better control of the fabric tension in the roll could be maintained for deformable and bulky materials. The pure center coil without pressure point is known for some delicate materials, but in this case the tension has been high and it may be necessary to apply an adequate pressure in the roll and the stretch in the direction of the machine can be reduced. With a pure center winding, the tension near the core needs to be higher to avoid telescoping the roll and other defects. And winding of pure center also suffers from speed limitations. At higher speeds, the tension of the fabric will be very high and the ripple of the sheet will lead to breaks and a poor winding.

Most tissue machines in the commercial operation have what is called an "open pull" between the dryer and the reel, meaning that the dry sheet is held over the distance between the dryer and the reel. More recently, in an effort to improve productivity by reducing the manufacturing sheet breaks, a tissue machine has been designed to include a support fabric to bring the dried sheet from the dryer to the reel without an open pull. Such a machine, as described in U.S. Patent No. 5,591,309 issued to Rugo ski et al., Entitled "Machine for Making Paper to Make Continuously Dried and N-Creped Tissue Sheets" illustrates a hard pressure point. between the reel slicer or the parent roll and the winding drum to effect the transfer of the sheet from the cloth to the spool or to the parent roll. For many tissue sheets, the presence of the hard pressure point with this point in the process is a problem because the sheet is relatively dense and can withstand the amount of compression experienced without detriment to the quality of the final product. However, for some recently developed tis leaves, particularly the continuously dried non-crepe dried non-creped continuous sheets of high volume and smooth as described in the United States of America No. 5,607,551 issued to Farrington et al., It has been found that traditional winding methods are capable of reliably producing a parent roll with an appropriate fabric tension and a radial tension through to give an unrolled sheet yield of substantial uniformity.

Therefore there is a need for a method of coiling bulky and soft tissue sheets in which the variability of the sheet volume, the gauge, the stretching of the machine direction and / or the basis weight are minimized while still being maintained. the characteristics of parent roll that are favorable for manufacturing and conversion operations Synthesis of the Invention It has now been discovered that voluminous and smooth tis sheets can be rolled onto a parent roll with minimal sheet degradation by bringing the sheet from the dryer to a motor-driven reel slicer while held by a transfer belt, preferably, it has little or no air permeability. The transfer belt traverses a free space not supported between two winding drums and transfers the sheet to the parent roll at a point where the transfer belt and is not in contact with the winding drums, generally at a point a length of an unsupported extension about halfway between the winding drums. At the point d transfer, the reel slicing of the parent roll is pushed only slightly against the sheet / transfer web d so that the transfer band is slightly deflected or arched. It has been found that the degree of deflection is an important variable that must be controlled to improve the uniformity of the sheet through the resulting parent roll. The deflection control is preferably achieved by directing a laser or other distance measurement devices on the underside of the transfer band to detect the degree to which the transfer web is deflected at the sheet transfer point. If the transfer band is deflected beyond a finish limit, the position of the reel relative to the transfer band is adjusted to either increase or decrease the distance between the reel slicing and the transfer belt. By controlling this distance to a small value during the entire time that the parent roll is being constructed, the force of the pressure point between the parent roll and the surface of the transfer band is minimized to a level which is much lower than that which can be achieved from the hard pressure point of the pressure rod. This in turn eliminates the effects of stretching the pressure point and secondary winding while allowing the tissue tension dictated by the central drive to be a larger factor in the control of the interlayer tension of the roll. The associated inlays with measuring the small pressure point forces and changing the bearing friction during the construction of rolls becomes completely obvious. The parent rolls wound on a furler according to this invention have an internal pressure distribution such that the peak pressure in the core region reaches more values. low _that- those, achieved -_- of a conventional carret, but still which are sufficient to maintain the mechanical stability required for normal handling. The parent rolls of the method of this invention have an inner pressure close to the core that decreases to a certain level then exhibit a significant region with an essentially flat pressure profile, except for the inevitable drop to the low pressure on the outer surface of the roll. Therefore, the uniformity of the sheet properties through the padr roll is essentially improved.

More specifically, the method of winding and weaving high-volume tissue onto a driven spool or coiling power in the center to form a padroll includes the steps of: (a) supporting the tissue of dry tissue on a transfer belt endless moving which leads to the tissue of the parent roll and which crosses a stretch not supported between two winding drums; (b) transferring the tis sheet while it is held by the transfer belt in the space between the two winding drums, the parent roll d so that the path of the transfer belt is deflected by the surface of the parent roll; (c) perceiving the extent to which the transfer band is deflected with a sensing device; and (d) adjusting the relative position of the slicer, spool and transfer belt in response to the extent to which the transfer is deflected by the parent roll. Adjust the relative positions of the reel slicer and transfer belt that can be achieved by either moving the reel slicer shaft or the transfer belt through its supporting mechanisms. In adjusting the relative position of the transfer belt and the reel slicer, the radius of the construction roll can be calculated by directing the measurement or by means of the relative position of the reel slicer shaft of its starting position and the deflection of the transfer band.

Control of the fabric properties of unwound fabric from the parent roll can be aided by imparting the incoming tissue in a predetermined amount of tissue tension, such as by programming the level of velocity difference between the transfer band and the surface exterior of the parent and construction roll. In most cases, a positive pull on the parent roll is required in order to impart the necessary fabric tension to provide a stable parent roll. On the other hand, too much positive pull will unacceptably reduce the stretch in the direction of the machine in the fabric. Therefore, the amount of positive pull (the percentage by which the speed of the surface of the parent roll exceeds the speed of the transfer belt) will depend on the properties of the fabric that comes to the parent roll and the desired properties. of fabric that is going to roll up from the parent roll. Generally the surface velocity of the parent roll will be about 10% or less faster than the speed of the transfer band, more specifically from about 0.5 about 8% faster and even more specifically from about 1. to around 6% faster. Of course, if tissue approaching the parent roll already has a sufficient tension provided by other means previously in the tissue manufacturing process, a negative draw of 0 may be desirable.

Therefore, in one aspect, the invention resides in a parent roll of a high volume tissue having a diameter d about 70 inches or greater, wherein the volume of the tissue taken from the roll is about 9 cubic centimeters per gram. greater, the coefficient of variation of the finished weight bas is about 2% less and the coefficient d of the stretching in the machine direction is d around 6% or less. In addition, the sheet volume variation coefficient for the tissue sheets taken from the padroll can be about 3.0 or less.

More specifically the diameter of the padr roll can be from about 100 to about 150 inch or greater. The - coefficient < The final weight-base variation can be around 1% or less. The coefficient of variation of the stretch in the machine direction can be d around 4% or less, even more specifically around 3% or less. The coefficient of variation of the leaf volume may be around 2.0 or less.

How it was used here, high volume tissue tissues that have a volume of about 9 cubic centimeters or more per gram before calendering. Such tissues are described in U.S. Patent No. 5,607,551 issued March 4, 1997 to Farrington Jr. others, entitled "Soft Tissues" which is incorporated herein by reference. More particularly, high volume tissues for the purposes mentioned herein can be characterized by volume value of from about 10 to about 35 cubic centimeters per gram, more specifically from about to about 25 cubic centimeters per gram. The method for measuring volume is described in the other Farrington patent. Furthermore, the softness of the high volume tissues of this invention can be characterized by a relatively low stiffness as determined by the maximum inclination in the machine direction and / or by the machine direction stiffness factor, the measurement of which it is also described in the pate of Farrington Jr. and others. More specifically, the maximum inclination in the machine direction expressed as kilogram per 3 inches of sample, can be from about 10 less, more specifically about 5 or less, and even m specifically from about 3 to 6. The machine direction rigid factor, expressed as (kilograms per inch) -mieras05, can be from about 150 or more specifically from about 100 or less and even m specifically from about 50 to about 10 In addition, the high volume tissues of this invention may have a stretch in the machine direction about 10% more, more specifically from about 10 to about 30% and even more specifically from about 15. In addition, the high volume tissues of this invention can suitably have a substantially uniform density since these are preferably dried in a continuous form to a dry one. final d without any significant difference compression.

Suitable contact and contact sensing devices useful for the purposes mentioned herein are well known in the art. Several are described by F.T Farago and M.A. Curtis in the work "Manual of Dimensional Measurements," 3rd edition, Industrial Press, Inc., New York, 1994. Such methods include laser-based distance-depth sensing devices that use such techniques as laser triangulation; white laser light or multiple wave moiré interferometry as illustrated by Kevi Harding, in the work "Moiré Interferometry, for Industrial Inspection", Lasers and Applications, November 1993, page 73-7 and by Albert J. Boehnlein, "Moire System of Change of Field ", patent of the United States of America No. 5,069,548 of December 3, 1991; Ultrasonic perception including the methods described by L.C. Lynworth, Ultrasonic Measurements for Process Control, Academic Press, Boston, 1989, particularly the method of delay time measurement for an ultrasonic signal reflected off a solid surface radar and microwave wave reflectance methods; methods d capacitance to determine the distance; current transduction methods; Formation of single chamber steroscopic images for depth perception as illustrated by T.

Lippert "Formation of Images in Third Dimension Binoculare Parallel and Radial" in the work "Optics of System Exhibit II", Proc. SPIE, volume 1117, pages 52-55 (1989) multiple camera stereoscopic imaging to perceive the depth, as illustrated by N. Alvertos "Integration of Stereo Camera Geometries" in optical illumination and image perception for machine vision I Proc., SPIE, vol. 1194, pages 276-286 (1989); d contact devices, such as rollers, reels, metal strips and other devices whose position or deflection is measured directly; Similar. A particularly suitable sensor device is a laser displacement sensor, model LAS-8010, manufactured by Nippon Automation Company, Ltd., distributed by Adsens Tech Inc.

The extent to which the transfer belt is deflected properly maintained at a level of about 20 millimeters or less, more specifically about 1 millimeter or less, even more specifically about millimeters or less, and even more specifically from around 1 to about 10 millimeters. The deflection is measured perpendicular to the unobstructed line of displacement of the transfer band. The acceptable amount of deflection for any given tissue sheet is in part determined by the design of the transfer belt and the tension imparted by the transfer belt during operation. As the tension is reduced, the acceptable amount of deflection will increase because the compression of the blade is reduced and the amount of power transferred to the parent roll is reduced. In addition, the variability of the properties of the winding sheet s reduces. Preferably the deflection of the transfer belt is maintained at a small amount so that the potenci transferred from the belt to the construction roll, or vice versa is about 10% of the drive motor load centered or less, more specifically from about 5% or less, even more specifically about 2% or less and even more specifically about 1% or less.

The preferably useful transfer band deflection control uses one or more laser distance sensors that determine the indentation. of the parent roll on the surface, d the band and then place the mobile linear carriers that hold and carry the parent rolls to maintain this indentation at a constant level. The laser sensor can be placed to always measure the deflection of the transfer band at the mid point of free extension, regardless of the position of the parent roll and the current deflection can be calculated as described below. Alternatively, the laser sensor can traverse the free space with the pressure point of the parent roller so that the lasers always measure the deflection directly. The control system preferably maintains the actual transfer band deflection at the pressure point at a level of about 4 mm ± 2 mm. The laser sensor can be a Nippon Automation LAS 8010 sensor that has a focused range of 140 to 60 millimeters. The sensor front plate can be mounted 120 millimeters from the inner surface of the transfer belt. Such a sensor is designed to give from 4 to 20 ma of output at the minimum to maximum distance between the sensor and the transfer belt. The winder then operated without a roll loaded against the transfer belt to put the zero point in the programmable logic controller.

The situation where the laser position is fixed at the midpoint of the free expansion and a deflection is measured by the laser at that point, the actual deflection at the parent roll pressure point was calculated according to the position of the parent roll at construction which crosses from one end the extension open to the other while it is being built. Since the laser is mounted in the middle of the free transfer belt expansion between the two winding drums and only the deflection of the transfer band in that position the actual deflection at the pressure point is approximately approximated by the measured deflection in the middle of the free space times in the proportion of the distance from the laser measurement point to the pressure point of the winding drum m near the pressure point of the parent roll divided by distance from the pressure point of the parent roll to the pressure point of the that same winding drum. For the purpose of this calculation, the pressure points of the wound drums d are the target points at which the deflected line n of displacement of the transfer belt in free space makes contact with the winding drums. The pressure point of the parent roll is the midpoint of the sheath of the transfer belt around the periphery of the parent roll. This is illustrated in Figure 3, where the actual deflection "D" is the deflection measured at the point M (the average point of free space) times the proportion of the distance MA the distance CA. If the parent roll were precisely in half the free extent, the ratio would be one and the laser would be measuring the actual deflection "d". However, when the parent roll is placed on either side of the middle point of the free extension, the. deflexlon. band d transfer measured by the laser at the midpoint always e less than the actual deflection in the transfer.

Once the deflection of the transfer band d has been measured, a given solid control circuit maintains the deflection at a constant level. The output of this control is the fixed point for a hydraulic servo positioning control system for the cars that hold the parent roll under construction. When the deflection of the transfer band exceeds the fixed point, the fixed point of the carriage position is increased, moving the carriages out of the fabric to return the deflection back to the fixed point. A specific hydraulic servo positioning system consists of Moog servo valves controlled by an Allen Bradley module with Temposoric transducers mounted on the hydraulic cylinder rods to determine the position. The output of the deflection control circuit is the input to the positioning systems to a servo on either side of the reel. Each system can then control by keeping the two sides of the spool parallel. There must be a system protection that stops the protection and the parallelism is lost but it is not necessary to have an active system to keep the two sides parallel. The air permeability of the transfer band can be from about 100 cubic feet per minute per square foot of fabric or less, more specifically from about 5 to about 50: cubic feet per minute per square foot and even more specifically from around d 0 to about 10 cubic feet per minute per square foot. L air permeability, which is the flow to the air through a fabric that maintains a differential air pressure of 0. inches of water through the fabric is described in the ASTM D737 test method. In addition, the transfer bar is preferably smoother than the continuous drying fabric in order to increase the transfer of the sheet.

The length of the unsupported extension between the winding drums requires being sufficiently long to allow the reel slicing to be placed between the first winding drum or winding up and the padroll fully controlled, the free extension requires sufficient cut to avoid bagging of the fabric so that the amount of tension can be minimized and the deflection grad can be controlled. A suitable length of libr expansion can be from about 1 to about meters, more specifically from about 2 to about 3 meters.

As mentioned previously, an advantage of this method is the improved uniformity resulting in the unrolled sheet properties of the parent roll. Large parent rolls can be rolled while substantial sheet uniformity is still provided due to the control of the roll pressure on the sheet, and soft high-volume tissue sheets can be rolled up in parent rolls at high speeds. Suitable machine speeds can be from about 3000 to about 6000 feet per minute or more more specifically from around 4000 to around 6000 feet per minute or greater, and even more specifically around 4500 to about 6000 feet by minutes.

Brief Description of the Drawings Figure 1 is a schematic process flow diagram of a method for making high and soft volume tissue sheets according to this invention.

Figure 2 is a schematic diagram d shown in Figure 1.

Figure 3 is a schematic diagram of a winding section illustrating a section of a laser displacement sensor for controlling the transfer d band shift.

Detailed Drawing Description Referring to FIG. 1, a schematic flow diagram of a continuous drying process for making continuously uncreped dried tissue sheets is shown. A headgear 1 is shown which deposits an aqueous solution of fibers for making paper on an inner forming fabric 3 as it passes through the forming roll 4. The outer forming fabric 5 serves to contain the fabric as it passes over the forming roll and throw some of the water The wet fabric 6 is then transferred from the inner forming fabric to a wet end transfer fabric 8 with the aid of a vacuum transfer shoe 9. This transfer was carried out with the transfer fabric moving at a slower speed. that of the forming fabric (rapid transfer) to impart the stretch to the final tissue sheet. The wet fabric is then transferred to the continuous drying cloth 1 with the aid of a transfer roller with vacuum 12. The continuous drying cloth carries the fabric over the continuous dryer 1 which blows hot air through the fabric to dry it while drying. that the volume is preserved There may be more than one continuous dryer in series (not shown) depending on the speed and capacity of the dryer. The dried tis sheet 15 is then transferred to a first dry end transfer cloth 16 with the aid of the roller transfer roller 17. The tissue sheet shortly before the transfer is in the form of a sandwich between the first sheet of paper. dry end transfer and transfer belt 1 to positively control the path of the sheet. The air permeability of the transfer band is lower than that of the first dry end transfer fabric causing the sheet to adhere naturally to the transfer band. At the point of separation, the sheet follows the transfer band to the vacuum action. Low air permeability fabrics suitable for use as transfer belts include, without limitation, the COFPA Mononap N 50 felt dryer (air permeability of about 50 cubic feet per minute) and Asten 960C (air impermeability). The transfer band d passes over two winding drums 21 and 22 before returning to pick up the dried tissue sheet again. The sheet e transferred to the parent roll 25 at a point where between the winding drums, the parent roll is wound on a spool 26, which is driven by a central driven motor Referring to Figure 2, the transfer and winding The sheet is illustrated in more detail. In the free extension between the two winding drums, the sheet 15 makes contact transfers to the parent roll 25. The reference numerals 26, 26 and 26"illustrate 3 positions of the spool during continuous operation., a new reel 26"is ready to advance to the position 26 'when the padroll 25 is being built. When the parent roll has reached its final predetermined diameter, the new reel is lowered by the arm 27 to the position 26' against of the incoming sheet at some point of free extension between the winding drums, generally relatively close to the first winding drum 21, thus avoiding a hard pressure point between the winding drum and the spool. appropriately by the support arms 28.- When being constructed; the parent tree, the carret moves towards the other winding drum 22 while at the same time it moves away from the transfer belt. The carriage can be moved in any direction as illustrated by the double-ended arrow to maintain the deflection of the proper transfer band necessary to minimize the variability of the sheet properties during the winding process. As a result of this, the pressure point of the padr roll essentially traverses the free extension when the roll is constructed to its predetermined size. At the appropriate time, one more air jets 30 serve to blow the return sheet towards the new spool 26 'in order to hold the sheet to the new spool by vacuum suction inside the spool. When the sheet is transferred to the new reel, the sheet is broken and the parent roll is kicked out to continue the process of rolling with a new reel.

Referring to Figure 3, the control of the relative positions of the reel 16 and the transfer band 18 is suitably achieved by using a non-contact perception device 35 which is focused within the transfer band, preferably in the middle of the point "M" between two winding drums as shown The object is to minimize and control the pressure exerted by the padr roll against the blade held by the transfer belt as well as to minimize the pressure point length created by the The sensing device as a sensor, the laser displacement, detects changes in the deflection of the transfer band as small as 0.005 in. (The n deflected line of transfer of the transfer band in the free extension certified with the number reference 36) E calculation of the deflection of the reference band using the ratio of the distance from the rolled drum tangent point "A" to The laser point "M" and the distance from the tangent point of winding drum "A" to the center of the point d of the parent roll "C" has been previously discussed. If the amount of deflection "D" is outside a predetermined acceptable range, the sensor emits signals that the parent roll reel has been set accordingly. The mechanical and electrical apparatus for positioning the reel in response to sensor input are not part of this invention and suitable means to achieve this objective can be designed or constructed by those skilled in the art of constructing speed reels. It has been found that the optimum rolling operation for the high-volume soft tissue sheets was achieved when deflection of the transfer belt is maintained at about 2 to about 6 millimeters. Transfer band deflection maintenance within this range was found to allow the parent roll and the transfer to operate at a relative speed difference without significant transfer of power. This will allow control of the winding process to maintain essentially constant velocity properties across the parent roll, which here had not been possible for such sheets using the conventional reels.

It will be appreciated that the foregoing description given for purposes of illustration is not intended to limit the scope of the invention which is defined by the following clause and the equivalents thereof.

Claims (7)

R E I V I N D I C A C I O N S

1. A parent roll of tissue having a diameter of about 70 inches or greater, wherein the volume of the tis taken from the roll is 9 cubic centimeters or greater per gram of the coefficient of variation of the finished tissue base weight is about 2% or less and the coefficient of variation of the stretch in the direction of the tissue machine is d around 6% or less.

2. The parent roll as claimed in clause 1, characterized in that the coefficient of the sheet d of the volume sheet of the tissue is about 3. or less.

3. The parent roll as claimed in clause 1, characterized in that the coefficient of variation of leaf volume of the tissue is about 2.0 or less.

4. The parent roll as claimed in clause 1, characterized in that the diameter of the parent roll is from about 100 to about 150 inches.

5. The parent roll as claimed in clause 1, characterized in that the coefficient of variation of the finished base weight of the tissue is about 1% or less.

6. The parent roll as claimed in clause 1, characterized in that the coefficient of variation of stretch in the direction of the tissue machine is d about 4% or less.

7. The parent roll as claimed in clause 1, characterized in that the coefficient of variation of stretch in the direction of the tissue machine is d about 3% or less. E S M E A uniformly rolled parent roll of high volume and soft tissue has greater uniformity in the base weight of the sheet, greater stretching in the machine direction and volume when compared to parent rolls rolled by means of conventional rolling method. The method involves carrying the tissue sheet over a relatively water-impervious transfer band which traverses a non-sustained extension between two winding drums. The sheet is transferred from the transfer band to the parent roll when the parent roll is pushed against the sheet / transfer band at a point within the unsupported extension. The resulting deflection of the transfer band detects and, in response, the position of the spool is controllably changed to maintain the deflection within the predetermined limits. The leaf tension is controlled by the predetermined differential speed between the outermost surface of the parent roll and the transfer band.