SI20065A - Stack of sheets with repositionable adhesive altrenating between opposite edges and containing one or more sheets different from other sheets - Google Patents

Abstract

The present invention provides a stack of flexible sheet material (200) comprising a plurality of sheets (201) disposed one on top of another, each sheet having repositionable adhesive (202) along one edge and being free of adhesive along the opposite edge and the sheets are stacked with the repositionable adhesive edge of each sheet disposed along alternate opposite edges to maintain the sheets in the stack, characterised in that said stack comprises at least two sheets that are different from each other. The present invention also provides a method and apparatus for obtaining a stack of sheets as defined above and a dispenser comprising a stack of sheets as defined above.

Description

STOCK OF SHEETS WITH REMOVABLE ADHESIVES, EXCHANGING BETWEEN OCCASIONAL EDGES AND CONTAINING ONE OR MORE SHEETS OTHER THAN OTHER SHEETS

Technical area

The present invention relates to a stack of flexible sheet material and to a dispenser containing such a stack. The stack contains a large number of sheets, each sheet being attached to the other by a repositionable adhesive and at least two sheets being different from each other. (Removable adhesive is an adhesive that allows peeling and re-gluing). The present invention further relates to a method for applying a coating material to a plurality of sheets, at least two sheets of which are different, and to a device for performing this process.

BACKGROUND OF THE INVENTION

US 5,417,345 discloses a dispensing apparatus for use in dispensing sheets of material coated along one edge with a narrow strip of easily detachable adhesive. The dispensing apparatus comprises a container having a pair of side walls connected to an upper wall formed by a transversely extending rectangular opening extending in a direction parallel to the side walls. The sheets are stacked inside the dispenser so that, after removing the highest sheet in accordance, a coating of adhesive along one edge of the sheet pasted at the edge of the next sheet will ensure that the next sheet is removed at that free edge through the distribution opening after removing the highest list. A typical embodiment shown includes a stack of sheets where the adhesive alternates between two opposite edges of the stack. In addition, dispensing devices, such as those shown in this patent, are commercially available. However, the stack of leaves used here is typically composed of leaves that are all similar.

There is now a desire to have one or more sheets different from the other sheets in the stack in the holdings of such distribution papers. For example, it may be desirable to have alternating color sheets, or to have one or more sheets containing a message, a special warning or a tag to approach the end of the stack.

However, so far it has not been possible to produce such stacked sheets where adhesive is exchanged between

-2the opposite edges. In particular, a stack of sheets, as shown in US 5,417,345, is typically prepared by coating adhesive strips on a continuous set of sheet material, such as paper. Such a procedure does not give the required flexibility required to produce stacks in which one or more leaves are different from other leaves,

WO 94/19419 publishes a process for coating a large number of individual sheets of adhesive, such as removable adhesive. This process allows one or more sheets other than the other sheets to be inserted during the coating process, thereby creating a stack of sheets with inserts. However, the process shown in this patent application is not adapted for the manufacture of stack pads, where the adhesive is exchanged between opposite edges of the stack and which can be used in a dispensing apparatus as shown in US 5,417,345 above.

Summary of the Invention

The present invention provides a stack of flexible sheet material comprising a large number of sheets arranged on top of each other, each sheet having a removable adhesive along one edge and without adhesive along the opposite edge, and the sheets are stacked with a removable adhesive of each sheet, arranged along alternating opposite edges to keep the leaves in a stack, characterized in that said stack comprises at least two sheets that are different from each other.

The present invention also provides a dispensing device comprising a stack of sheets as defined above, said dispensing apparatus having accessories for the walls surrounding the stack, including an upper wall with a transverse opening through which the edge portion extends without the adhesive of the highest sheet in accordance.

The present invention further provides a method for applying a coating material to sheets comprising the following steps:

(a) applying the coating material to an endless transfer surface;

(b) transporting a large number of leaves, at least two of which are different from one another, in an end-to-end overlapping connection to the transfer location; and

-3 (c) contacting the sheets at the transfer site with the transfer surface to transfer the coating material to the sheets, thereby obtaining a coated surface on each of said sheets;

wherein said coating material is applied to said infinite transfer surface such that when the coating material is transferred to the first and second sheets adjacent to each other, the coated surfaces on said first and second sheets are offset relative to each other in a direction perpendicular to the leaf transfer direction.

A device for applying coating material to a large number of sheets is also provided, the device including a transport device for transporting a large number of sheets in an end-to-end covered connection to the transfer location;

an endless transfer surface that moves through the transfer location in contact with the transported leaves;

and a coating means adapted to apply a coating material to the endless transfer surface for later transfer to the sheets to form coated surfaces at the transfer site;

wherein said coating agent is capable of applying coating material to said infinite transfer surface in such a way that when the coating material is transferred to the first and second sheets closest to each other, the coated surfaces on said first and the second sheet is displaced relative to one another in a perpendicular direction to the direction of transport of the leaves.

Brief description of the drawings

Embodiments of the invention will be described by way of example, with reference to the accompanying drawings, wherein the same structure is assigned the same numbers in different views and in which:

Figure 1 is a schematic side view of a sheet coating apparatus according to the invention;

Figure 2 is a schematic floor plan of the device shown in Figure 1;

4FIG. 3 is a schematic illustration of the relative positions of the leaves at the entrance to the part forming the device for double coating the device shown in FIG. 1;

Figure 4 is a view of the part forming the dual coating device of the device shown in Figure 1;

Figure 5 is a view similar to Figure 4, showing a portion of the dual coating preparation in more detail;

Figure 6 shows the feed system for the coating material for the dual coating preparation of Figures 4 and 5;

Figure 7 is an enlarged view of the work in Figure 5.

8 is an enlarged schematic view illustrating a portion of the apparatus shown in FIG. 1;

Figure 9 shows the component of Figure 8;

Figure 10a is a schematic side view of a component portion forming an adhesive coating device of the device shown in Figure 1;

Figure 10b is a schematic view of an engraving roller for use in an adhesive coating preparation shown in Figure 10a;

Figure 10c is a schematic representation of a continuous transfer coated with adhesive lines using the engraving roller shown in Figure 10b;

Fig. 11 is an enlarged partial view illustrating schematically a portion of Fig. 10a;

12 is a partial plan view of the component of FIG. 11; and

Figure 13 is a partial floor plan of the second component of Figure 11.

Figures 14a through 14c schematically illustrate the trimming of a stack of leaves into desirable blocks

-5 size and shape.

Detailed description

The flexible sheet material for use in the present invention can be any type of flexible material and includes paper as well as plastic film materials such as polyethylene, polypropylene and polyester. Preferably, the material of the flexible sheets is paper and the description will primarily be directed to this, but without the intention of limiting the invention to this. Preferably, the flexible sheet material stack is a stack of movable sheets. Preferably such sheets are coated on one surface with a primer coating and on the other with a low adhesive back adhesive (LAB). The adhesive is applied to the surface coated with a primer. Priming material can be obtained by mixing about 3-7% (w / w) of MOVVIOL binder (brand), obtainable from Hoechst AG, Frankfurt / Main, Germany and about 3-8% (w / w) of AEROSIL pigment (trademark), obtainable from Deguss AG, Frankfurt / Main, Germany with about 90% (w / w) water.

The LAB material may be any suitable material including, but not limited to, acrylic copolymers, silicone materials, urethanes and fluoro polymers. The LAB, for example, may be a water-based solution of the material described in EP-A 0618509, the solution typically comprising from about 5% to about 10% solid material. Other materials for LAB that may be used include those published in United States Patent No. No. 5,202,190 and 5,032,460.

Removable adhesive is preferably a removable microspherical pressure adhesive, for example, as described in US-A-5 045 569; 4 495 318; 4 166 152; 3 857 731; 3 691 140; US Re 24906; US 5,571,617 and EP-A-0 439 941.

The leaves of the stack may be of any size and shape desired, but are typically rectangular or square and have a width of between 5 cm and 15 cm and a length of between 5 cm and 25 cm. The number of leaves in a stack can vary greatly, but is typically between 10 and 100, preferably between 25 and 50.

The stack of the present invention contains at least two sheets that are different from each other. While they may be different in any type of view, they are preferably different in color, print or type of material. Depending on the particular embodiment of the present invention, the stack contains most of the leaves,

-6s are similar and few leaves different from most leaves. Typically, these few sheets may contain messages such as a warning or a sign that the end of the stack is approaching. Alternatively, the stack comprises similar first leaves and similar second leaves and these first and second leaves differ from each other, for example in color and are exchanged throughout the stack.

The flexible sheet material according to the present invention has a first larger surface and a second larger surface opposite the first larger surface. A removable adhesive, preferably in the form of a strip or strip, is prepared along one edge of the other larger surface, although any other shape, such as freckles of a removable adhesive, may be used. The sheets are folded together so that the second larger surface of one sheet is firmly held on the first larger surface of the next sheet, and the adhesive coating is exchanged between two opposite edges of the stack. Therefore, of two consecutive sheets of the stack, one sheet will have a removable adhesive along the first edge of the two opposite edges and will have no removable adhesive along the second edge of the two opposite edges, and the next sheet will have no removable adhesive along the first edge and have a removable adhesive along the other edge.

The stack of flexible sheet material of the present invention is typically used in a dispenser as described above. This adds to the commercial advertisements contained in the inserted sheets in accordance, a surprise element, since such sheets appear to the user only when the previous sheet is removed from the dispenser according to the inserted sheet. Suitable dispensing devices for use in the present invention are described in more detail in US 5,417,345.

Preferred device and process for coating flexible sheet material

The apparatus shown schematically in Figures 1 and 2 is specific for use in the manufacture of removable sheets made from sheets of any suitable substrate material, such as paper, polymer film or foil, and especially for the application of a priming material, low adhesive backing (LAB) material and removable adhesive onto individual sheets so that the sheets can be used later to form removable sheets. In the following description, we will assume, unless otherwise noted, that the sheets (which may be pre-printed) are of paper. Paper can be any suitable paper, such as paper used to assemble the Post-it relocation sheets obtained from Minnesota Mining and Manufacturing Company (“3M”) from St. Paul, Minnesota.

-7The machine has a paper line that receives a continuous series of paper sheets (not shown) from the stack in sheet feeder 1. From the sheet feeder 1, the sheets travel along the paper line in the direction indicated by arrow 100, past the sheet feeder 2 (which, as shown in Figure 2, is mounted on one side of the paper line) and then through the paper feeder 3. double coating, sheet covering station 4, dryer 5, guide sheet 6 for sheets and adhesive coating device 7. The control and synchronization of the drives of different stations can be performed with a central electronic control unit (not shown), for example Siemens PLC 135.

As described in more detail below, leaves, if the insertion device 2 is not in use, feeder 1 in a continuous stream in which the back edge of one sheet overlaps the first edge of the next sheet to reduce the required space between the feeder 1 and the feeder 3. double coating. However, the sheets are transported separately through the double coating device 3, where they are individually coated on one side with a primer and on the other with LAB. The sheets coming from the double-coating device 3 are then re-covered in a pseudowire-forming overlay station 4, in which the back edge of one sheet is covered with the first edge of the next sheet. The pseudonise is then maintained throughout the remainder of the apparatus, although the initial direction of coverage, which is undesirable for the dryer 5 and is not suitable for the adhesive coating preparation 7, is omitted when the pseudowire leaves station 4 for overlay. After passing through the dryer 5 (in which the coatings of the priming agent and the LAB are dried), the pseudo-string passes through the guide part 6 (in which the leaves are laterally arranged and aligned and the adhesive coating device 7 (in which a large number is applied to the sheets adhesive strips on the side coated with priming material in the double-coater 3) The sheets can then be folded and cut as required to form removable leaf blocks. Alternatively, sheets leaving the dryer 5 may be they are folded and stored and later fed back, like a pseudo-string of covered leaves, to the glue coating preparation.

The insertion device 2, which is not an essential part of the device, can be used when it is required that one or more sheets from another stack be inserted into the flow of sheets entering the dual coating device 3. Alternatively, for the production of the stack of the present invention, a stack of uncoated sheets with one or more different sheets inserted may be supplied from the sheet feeder 1. The insertion device 2 may be as described in our patent application GB serial no. 9603345.1, filed Feb 16, 96 and entitled 'Sheet coating method and apparatus with sheet insertion (=' Sheet coating method and apparatus for inserting sheets).

-8Now we will detail the operation of the 1 sheet feeder. A sheet feeder is a rear edge feeder of a type comprising a vertically movable table 10 on which a stack of leaves 11 is mounted and a suction head 12 positioned above the rear of the stack edge. When feeder 1 is in operation, the suction head 12 lifts the top sheet from the stack 11 with its rear edge and moves it forward (supported by a jet of air from the nozzle 12a) by lifting the sheet with rollers 13 and transporting it from the feeder and to the conveyor 14. The suction head 12 then reverses and picks up the next sheet, which moves forward and rises with the rollers 13 while the first sheet is still present between the rollers. In this way, the back end of each sheet overlaps the first end of the sheet, which follows as the leaves go between the rollers and are fed to the conveyor 14. The degree of overlap depends on the size of the leaves and the ratio between the operation of the suction head 12 and the pickup speed 13. When the height of the stack 11 decreases, the table 10 moves upwards to maintain the top of the stack in a predetermined location relative to the suction head 12.

The leaf feeders of the type just described can be obtained from MABEG Maschinenbau GmbH from Offenbach, Germany under the trade code 41988. However, it will be understood that any other suitable leaf feeder could be used.

The sheets from feeder 1 are conveyed on the conveyor 14 past the sheet insertion device 2 to the door 15 at the entrance to the double coating device 3. For the purposes of the present description, it will be assumed that the sheet insertion device 2 is inoperative and in this case the overlay sheets from feeder 1 form a continuous stream on the conveyor 14, as shown in FIG. 3. When the first sheet 21 reaches the door 15, it is suspended while the upper and lower coating station rolls 16.17 (described below) rotate within the dual coating device 3 to the correct position for conveyors and sheet coating. The door 15 is then opened to allow the first sheet 21 to enter the double coating device 3, the door being closed before the arrival of the second sheet 22 and the last to be stopped until the upper and lower coating station rolls 16,17 are rotated back to the correct position.

The dual coating apparatus 3 shown in FIG. 4 and more in FIG. 5 and 6. The sheets from the conveyor 14 are picked up by a pair of gripping rollers 30 in the dual coating device 3 and fed between the upper coating station 16 and the lower coating station 17 (already mentioned), which are individually positioned above and below the line for the paper through the dual coating preparation. As the leaves go through preparing for the double

-9 coating, apply upper station 16 coating of primer material to one side of each sheet, and lower station 17 simultaneously apply coating of LAB material to the other side of each sheet. The sheets are fed to a 3-coater in a non-coated state. This exposes the entire surface or a substantial part of the two major leaf surfaces to LAB coating and primer. As described below, mechanical means are used to grip and move the sheets forward through the dual coating preparation, allowing the primer and LAB material to be coated over substantially entire larger surfaces of the sheets.

The upper coating station 16 comprises a metering roller 31 and a coating roller 32 mounted above the line of sheets of paper through a dual coating preparation. The coating roller 32 cooperates with the coating roller 33 of the lower coating station 17, which also comprises a metering roller 34 and a transfer roller 35, all mounted below the paper line through a double coating device. The coating roll 33 has a cut-out portion 36 of a rectangular section (shown in more detail in Figure 7) containing a conventional 37-sheet gripper (shown closed in Figure 7) for gripping the leaves from the feeder 30 for receiving. In addition, the cylinder about less than half of its circumference is covered by the lining 38 (not shown in FIG. 4) and thus, as described below, form a coating roller 32 and a coating roller 33 for gripping only when the lining is directly adjacent next to the coating roll 32. As described below, the upper coating station 16 provides substantially roller coating of all surfaces with priming material on the upper surface of the sheets, and the lower coating station 17 provides substantially roller coating of all surfaces with LAB material on the lower surface of the sheets . In any case, the parts occupied by the grips (as described here) shall not be coated.

In the upper coating station, a passage 39 is formed for the printing material with the surfaces of the dosing and coating rollers 31, 32 lying just at the grip between the rollers and on the upper side thereof, together with two opposite end walls (not shown) which are notched in the grooves ( not shown) lying just at the ends of the rollers. When the rollers 31, 32 rotate, it forms a primer on the coating roller 32 film and is transferred to a sheet that passes under the roller.

The thickness of the primer film on the coating roller 32, and thus the amount of primer agent coated on the sheet, depends on the viscosity of the primer and the pressure between the metering roller and the coating roller 31.32 and, for a given primer, can be

-10regulates by moving the metering roller towards or away from the coating roller and adjusting its speed. The passage 39 is provided with a primer for nozzles 40 (see also Figure 6), which receive a primer from the tank 41 by means of a pump 42. The passage 39 also has overflow outlets 43 through which the excess of the primer is returned to the tank.

In the lower coating station 17, a similar passageway 44 is formed for the LAB material between the metering roller 34 and the transfer roller 35. As in the upper station, the coating material forms a film on the transfer roller, the thickness of which can be controlled by moving the metering roller 34 towards or away from the transfer roller 35 and adjusting its velocity, thereby controlling the amount of LAB material exiting the roller. transfer to the coating of the liner 38 on the coating roll 33 (but not to the residue of the roll not touched by the transfer roll 35).

In the same way as passage 39 in the upper coating station 16, passage 44 is provided with LAB material with corresponding nozzles 45 (see also Figure 6), which receive LAB material from the corresponding tank 46 by means of pump 47. Passage 44 has overflow outlets 48 , through which the excess LAB material is returned to the tank 46. When the lining portion of the cylinder 33 rotates, lying adjacent to the coating roller 32 of the upper station, the sheet coming in from the feeder 30 of the double coating device 3 is picked up by the gripper. 37 in the cylinder and transferred through the gripping coating between the roller 32 and the lining 38 on the roller 33, and when the sheet passes through the gripping, it will be coated with LAB material on one side. The sheet removal devices (not shown) are mounted on the downstream side of the coating roller and the coating roller to ensure that the sheets do not wrap around either the roller or the roller but are taken to station 4 for overlap. The following sheet from feed roller grip 30 will be picked up and guided between the coating roller 32 and the coating roller 33 when the coating of the liner is rotated once more, lying adjacent to the coating roller 32, the operation of the door 15 being timed to ensure that the leaf lifts at each cylinder rotation.

At the moment when no leaf is waiting at door 15 (as a result, for example, incorrect feed at feeder 1 or insertion device 2), this fact is detected by a photocell (not shown) at the door, the roller 32 moves away from the roller 33 to prevent any mixing of primer and LAB material.

It will be appreciated that the coating in the dual coating preparation 3 is continuous because it only takes place when the coating 38 of the coating on the coating cylinder lies adjacent

-11coating roller 32 (ie, when the sheet goes through the gripping coating). The typical weight of the coating for the LAB material on the sheets is from 0.5 g / m ² to about 12.0 g / m ² , and the weight of the primer coating should be adjusted accordingly to ensure that the coated sheets remain level. As the priming material and the LAB material are applied to the paper sheets simultaneously in the coating station and are preferably selected to have suitably selected characteristics, such as viscosity,% solids and weight of the coatings, there is a danger of the sheets being wrinkled or crushed , essentially eliminated. Alternatively, a dual coating preparation that does not apply a primer and a LAB coating at the same time could be used, albeit with the loss of advantages associated with simultaneous coating. For example, the primer coating station 16 could be positioned in front of the LAB coating station 17, in which case the coating roller 32 and the coating roller 33 would each require a suitable counter-pressure roller.

The coating 38 of the coating on the coating roll 33 may be of any suitable type, but is preferably formed of rubber or any other suitable elastomeric material. The lining 38 is attached by adhesive to a thin sheet of support material 38A, which is capable of being wrapped around the cylinder 33 and loosely secured thereto. The support thin plate 38A may be, for example, plastic material such as those available under the trade name Mylar, and the lining 38 may be attached to a support thin plate with neoprene adhesive such as that obtainable under trade mark 1236 from Minnesota Mining and Manufacturing Company of St. Paul, Minnesota, USA. The 38 A thin support plate is loosely secured to the cylinder 33, for example by screws. In this way, the liner 38 can be easily removed from the cylinder and reinstalled when necessary. If the lining 38 is attached to the supporting thin plate 38A while the latter is extended straight, it is preferable to use a flexible adhesive to secure the lining. The flexibility of the adhesive is less important if the lining 38 is attached to the supporting thin plate after the latter is attached to the cylinder 33. Any suitable adhesive may be used to attach the elastomeric lining 38 to the supporting thin plate, especially provided that so that the corners of the liner do not rise away from the supporting thin plate during the coating process.

The coating roller as shown in FIG. 7 is also described in our patent application GB ser. no. 9603366.7, filed 02/16/96 and entitled Sheet coating apparatus including a coating roller (= Sheet coating apparatus containing a coating roller).

-12An alternative may be coating 38 liners on a coating roller 33 Du Pont CYRELL polyurethane liner, available from E.I. Du Pont de Nemours of Wilmington, Delaware, USA.

On the output side of the receiving 32.33 coating, there is a sheet overlay station 4, in which a gripping unit 50 is installed, which receives the leaves when they come out of the coating receiving and depositing them on the conveyor 51 (not shown in Figure 5). The conventional receiving unit 50 comprises grippers 52 of leaves supported by an endless chain 53 whose motion is synchronized with the addition of leaves so that the gripper 52 is positioned to receive each sheet leaving the gripping grip. The blower 54, located below the paper line on the outlet side of the coating grip, provides an air cushion that supports the sheets when carried by the 52 sheet grippers. The blower 54 includes a heater (not shown) that serves to dry the LAB coating on the sheet to some extent to prevent the sheets from sticking to the conveyor. The conveyor 51 is driven at a slower speed than the chain 53 of the gripping unit, so that each sheet is deposited on the conveyor with the first edge of the sheet lying at the top of the last edge of the previous sheet, forming a pseudo-row of leaves. Typically (but not significantly), the coverage size is from about 1 centimeter (cm) to about 2 cm. The conveyor 51 is a vacuum conveyor connected to the low pressure source 55 so that the leaves are firmly held on the conveyor and a covered connection is maintained between them.

The double coating machine 3 together with the sheet overlay station 4 may be based on the coating kit 'GULLA SPEED GS GS 8000, available from Billhofer Maschinenfabrik GmbH from Nuremberg, Germany.

From the output end of conveyor 51, the leaves move to a further vacuum conveyor 56 (Figure 1), which carries the leaves through the dryer 5 (described in more detail below). Between the conveyors, 51.56, the sheets pass through a device that reverses the direction in which the sheets are covered. This apparatus including the blower 60 shown in Fig. 4 is schematically shown in Figures 8 and 9. In addition to the blower 60 (which is located between the conveyors 51.56 and below the paper line), the preparation includes a stationary vacuum cylinder 61 with closed ends 62 , which is positioned above the paper line and slightly downstream of the blower. The part of the vacuum cylinder 61 directed toward the blower 60 is formed by a large number of openings 63 shown in Figure 9, with the remainder of the cylinder closed. In use, the inside of the cylinder is connected to a vacuum source 66 by line 67 through one of the closed ends 62. Typically, the cylinder 61 has a diameter of about 15 cm, and the openings 63 (these are three rows spaced 30 mm apart) have a diameter of 6 mm. spaced apart

-13for 30 mm in rows.

The device shown in Figure 8 operates as follows. The operation of the blower 60 is timed so that a discrete jet of air is directed at the overlap between each pair of consecutive sheets 64,65 (i.e., when the sheet 64 began to move on the conveyor 56 and the sheet 65 began to move from the conveyor 51), to raise the back end of sheet 64 and the first end of sheet 65 as shown in the broken lines in FIG. 8. The back end of the sheet 64 will then be influenced by the vacuum in the cylinder 61 acting through the openings 63 and pulled toward the cylinder where it will be held while the first end of the sheet 65 falls back onto the paper line. Sheet 65 now proceeds to move to conveyor 56, which at the same time pulls the back end of the sheet 64 away from the cylinder 61 and back onto the paper line, although it is now positioned above, rather than below, the first end of sheet 65.

It will be appreciated that the vacuum can be applied constantly because the vacuum in the cylinder 61 does not affect the sheets while they lie flat on the conveyors 51.56. The vacuum should be applied at a sufficient level to ensure that it can pull and hold the back end of the sheet (such as sheet 64 in Fig. 9), but not so large that the sheets cannot be removed by moving the conveyor 56 forward . If desired, a plate 68 may be mounted above the cylinder 61 and the blower 60, for example, as shown in Figure 8, to direct the jet of air from the blower towards the cylinder.

Any other design, including, for example, an air knife or equivalent mechanical device, such as the one described in GB-A-2 166 717, but with a loss, could be used to replace the direction of overlap between conveyors 51 and 56. the advantages associated with the implementation of Figure 8.

Returning to Figure 1, the pseudo-string of leaves now moves from the sheet overlay station 4 and into the dryer 5, in which moisture is removed from the coatings of the primer and LAB. Dryer 5 is preferably a radio frequency dryer, for example a specially adapted version of Model No. 2. SP 890 GFC-AG made by Proctor Strayfield Ltd. from Berkshire, England. The dryer 5 is equipped with a control unit (not shown) that regulates the power of the dryer according to the speed of the device line. This control unit may, for example, be a Siemens PLC 55 95U connected to a central electronic control unit of the entire device. The covered leaves move through the dryer 5 continuously on the endless strip 56 and dry at a rate that reduces the tendency of the leaves to wrinkle but which ensures that they come out essentially dry. The use of a radio frequency drier is not essential and the covered leaves could instead be dried using infrared heating or

-14 hot air. Alternatively, an endless strip 56 could be used to dry the sheets. However, due to its simplicity and lower energy consumption, radio frequency drying is preferred.

Although it is preferable to change the direction of leaf overlap before the leaves enter the dryer 5 (as described above), since the leaves are less likely to rise away from the strip 56, it is possible to delay this operation until the leaves are dried. In this case, the device shown in Figure 8 would be installed at the exit of the dryer 5.

In the downstream direction of the dryer 5, the coated sheets move through a guide portion 6 in which they are laterally arranged and aligned with one another in preparation for advancement to the adhesive coating device 7. In the adhesive coating preparation 7, the covered sheets pass through the transfer station (see also Figure 10a), where they come into contact with the transfer belt 71, to which the adhesive coating was previously applied. in the form of freckles or a large number of lines extending along the strip.

The conveyor belt 71 moves around rollers 72 of which at least one is driven so that the conveyor belt moves forward in the direction of the arrow 73. When the conveyor belt 71 moves (at the same forward speed as the covered leaves), it passes by the mechanism 74 coating, dryer 75 and transfer station 70, each of which will be described in more detail below. Preferably, the adhesive is at least partially dried (i.e., the moisture content is reduced to the desired level) in the dryer 75 before being transferred to the covered sheets in the transfer station 70. The moisture content of the water-based adhesive can be, for example, about 50% - 80% before drying and 0% - 50% after drying. Preferably, substantially all moisture is removed during the drying process.

The coating mechanism 74 applies a removable adhesive to the transfer belt surface 76. The coating mechanism may use, for example, a rotating engraving roller 77 to apply the adhesive. The engraving roller 77 (Figure 10a, 10b) comes into contact and extends beyond the width of the transfer belt 71 and has at least the first (770) and second formed on its surface. (771) Engravings. The first 770 and the second 771 engravings extend only around a portion of the circumference of the engraving roller 77 and are radially and axially displaced relative to each other such that the removable adhesive is applied to the conveyor belt 71 for transmission at the desired locations. The engravings 770, 771 are preferably in the form of a band into which the removable adhesive is applied in the form of adhesive lines, or the engraving may be in the form of a circle or an ellipse, so that a freckle of the removable adhesive is applied.

-15 Preferably, the transfer tape 71 also includes means 711 for synchronization, so that the transfer of the removable adhesive to the transfer tape 71 can begin at a predefined position (see Figure 10c). For example, the conveyor belt 71 may have a mark, for example in the form of a vertical line extending over the transfer belt 71 or a marking area, for example, a square along one edge. Such a marking can then be used to position the engraving roller 77 on that portion of the conveyor belt 71 such that the engraving roller 77 is in contact with the transfer ribbon 71 between the first 770s and the second engraving 771 when coating on the conveyor belt begins. To assist in the proper positioning of the engraving roller 77 with respect to the synchronization means 711 on the transfer belt 71, the gravity roller 77 may also include a synchronization means (not shown), for example, in the form of a character. The positioning of the engraving roller 77 at the beginning of the coating then results in a coating on the transfer belt 71, as shown in Figure 10c.

As shown in Fig. 10c, when the engraving roller 77 is in contact (not shown) between the first 770 and the second 771 engraving belts at the synchronization means 711 on the transfer belt 71, and then makes a half turn while maintaining contact between the engraving roller 77 and the conveyor belt 71, apply to the conveyor belt 71 the adhesive from the first gravum belts 770. By turning the engraving roller 77 further while in contact with the conveyor belt 71 to complete the complete turn, at conveyor belt applied removable adhesive from other gravity belts 771. Since the first 770 and second 771 gravure belts extend only around a portion of the circumference of the gravure roller and are radially or axially offset from each other, the adhesive coatings are from the first 770 and other 771 gravure belts resulting in transmit lane 71 are transversely offset and interrupted. Preferably, the length of the break in the adhesive lines corresponds to at least the length of the leaves in their direction of transport. So, if the beginning of the sheet is synchronized with the beginning of the adhesive line, the adhesive lines resulting from the first 770 and other 771 engravings will be applied alternately to the sheets.

Synchronization of the beginning of the sheet with the beginning of the adhesive lines can be accomplished by detecting the position of the transfer strip 71 and the beginning of the sheet. This can be done, for example, with a contrast cell that detects synchronization means 711 on the transfer band 71, and there is a black line at the beginning of each sheet that could also be detected with a contrast cell. The detection of the position of the conveyor belt 71 and the start of the sheet could then be used to adjust the conveyor belt speed 71 and / or the conveyance rate of the sheets to obtain suitable synchronization.

The adhesive to be applied to conveyor belt 71 by means of an engraving roller 77 is supplied with

-16 pump 78 from the tank 79 to the well 80 at the coating mechanism 74. The metering roller 81 is immersed in the glue in the bath and, as it rotates, picks up the metering roller glue, which is then transferred to the reversely rotating engraving roller 77 and especially to the engravings. One or more shear blades (such as 82) coincide with the engraving roller 77 to remove any excess adhesive and ensure that all adhesive on the engraving roller is contained only in the engraving cells, thereby ensuring that the adhesive is transferred to lines or spots on lane 71 for transmission.

The adhesive strip conveyor belt 71 then passes through the dryer 75 (Figure 1), in which the adhesive lines are dried at least partially (i.e., varying in the range of 0% - 50%). This is done to improve the adhesiveness of the adhesive to the sheets. The dryer 75 is preferably a radio frequency dryer, for example a specially adapted version of Model No. 1. SPW 12-73 by Proctor Strayfield Ltd. from Berkshire, England, typically regulated at about 27 MHz or alternatively, at about 30 MHz. The dryer is approximately 2.5 m long in the direction of travel of the belt and has a discharge (not shown) through which the interior of the dryer is ventilated by means of a fan 84. The dryer is equipped with a control unit (not shown) that controls the power of the dryer in accordance with the speed lines of coating machine. This control unit may, for example, be a Siemens PLC 55-95U connected to a central electronic control unit of the entire device.

A radio frequency dryer requires that the material of the transmission band 71 is non-reactive (i.e., transparent or otherwise unaffected by radio frequency radiation to a degree that adversely affects the operation of the process and apparatus of the present invention) to radio frequency radiation. This embodiment offers the advantage of drying the adhesive without significantly transferring the conveyor belt, thereby eliminating any heat transfer from the conveyor belt to the coating mechanism 74 and then to the adhesive, which could cause the adhesive to coagulate before being applied. to tape 71 for transmission. The radio frequency drier also offers the benefits of relative ease and lower power consumption. Further, conveyor belt 71 does not require prolonged preheating to a particular operating temperature, and the adhesive is easily transferred from the conveyor belt to the sheets at the coating station.

Preferably, the conveyor belt 71 comprises a base layer of fiberglass fabric, about 0.1 mm thick, coated on each side with a layer of about 0.15 mm thick silicone rubber.

However, it will be understood that other forms of transmission tape that are incompatible with a radio frequency drier (i.e., not transparent or inert to the radio) may be used

-17frequency radiation), though with the loss of benefits associated with a band that is non-reactive. The conveyor belt, for example, may contain a metal substrate with a silicone rubber coating on each side. Other types of dryers that can be used include, for example, an infrared heater or a hot air dryer. However, if the dryer causes the transfer tape 71 (and then the coating mechanism 74) to heat up, it may be necessary to cool the adhesive and transfer tape to reduce the risk of adhesive coagulation.

At the transfer station 70, the adhesive coated conveyor belt 71 is passed through the gripping 85 for transmission, comprising a transfer roller 90 and a stationary counter-pressure roller 91. The overlapped leaves 86 of the guiding portion 6 of the device are also routed through the transfer gripper 85, such as have already been mentioned and are supported by a pressure roller 91 against a transfer roller 90 and subsequently against a transfer roller 71 so that the adhesive is transferred from the strip to the sheets.

The counterbalance roller 91 at the transfer gripper 85 is provided with a large number of circumferentially spaced grooves 92 (FIG. 11), and a plurality of volumes 93 are prepared immediately behind the roller 90 to accommodate these grooves. The rollers 93 ensure that the overlapped leaves 86 continue their journey with the conveyor belt 71 after the leaves have left the gripper 85 for transmission and are not wound around the counter roller 91. The leaves 86 are removed from the conveyor belt 71 for the conveyor 93 with the separation conveyor in the form of a vacuum belt 95, which, as described below, also serves to transport the sheets to the output 96 of the paper line from the machine (Figure 10a). The direction in which the leaves overlap makes it easier to remove the leaves from the conveyor belt 71 (i.e., because of the fact that the first edge of each sheet is covered by the back edge of the previous sheet).

The additional roller 97 is prepared to fit inside the transfer belt 71 after the beginning of the vacuum strip 95 and is positioned to ensure that the transfer belt is tilted a small angle (about 1 to 3 degrees) toward the beginning (i.e., before the roller 97). vacuum strip and then (i.e., behind the roller 97) for a much larger angle (about 3 to 6 degrees). Typically, the angle for which the conveyor belt 71 is inclined toward the vacuum conveyor 95 is initially about two or three degrees by a distance of about 50 mm, while the vacuum conveyor serves to remove the leaves from the conveyor belt and then increases to about five degrees to increase the separation between the transfer tape and the sheets. The roller 97 is movable as indicated by arrow 97a to allow the angles between the transfer belt 71 and the vacuum strip 95 to be adjusted.

Vacuum strip 95 is connected to a low pressure source in vacuum compartment 99 and equipped

-18 with openings, as indicated by 98 in Fig. 13, by applying a reduced pressure to the sheets on the strip surface through the tape. The reduced pressure applied through the vacuum lane 95 is relatively strong above the initial portion of the lane run, where the relative pitch of the transfer belt 71 is lowest and then decreases as the relative slope of the transfer belt increases. To this end, a section 101 is formed in the vacuum compartment 99 and is connected through an opening 102 to a relatively low pressure source, while the rest of the vacuum compartment is connected through openings 103 to a more moderately reduced pressure source. In addition, the reduced pressure in section 101 is applied to the strip through relatively larger openings 104 in the surface of the vacuum compartment 99, while the reduced pressure in the rest of the vacuum compartment is applied through the reduced openings 105. The reduced pressure applied through the openings 104 is high enough. to separate the leaves from the conveyor belt 71 without damaging them and then descending above the remainder of the vacuum compartment 99 to a level sufficient to maintain the separate leaves on the vacuum conveyor belt without damaging them again (in this case, at case defined by openings 98) so that they can be transported to the output of the paper line. For example, a reduced pressure in the range of 350 to 550 mm H ₂ O (typically 400 mm H ₂ O) may be applied above the initial run of lane 75, at the same time as a reduced pressure in the range of 150 to 200 mm H ₂ O, which Applies over the rest of the run. In any case, the degree of pressure that can be applied is limited by the need to prevent damage to the leaves and will vary depending on the type of leaf material. Once separated from vacuum strip 95, the sheets can be folded and trimmed to form removable leaf blocks, such as those available under the Post-if trademark, which can be obtained from Minnesota Mining and Manufacturing Company (3M) from St. Paul, Minnesota. The vacuum strip 95 is not required to be a single strip extending beyond the width of the vacuum compartment 99, but could also comprise a large number of narrower strips arranged in parallel.

Figures 14a through 14c schematically show the trimming process. The stack of sheets 200 from the coating device shown in Figure 1 will thus typically comprise support sheets 201, first sheets 203 and second sheets 204, other than first sheets 203 with removable adhesive 202 coated on the back of sheets 203 and 204. As shown in Fig. 14b, the stack of sheets 200 is then cut with the help of knives 205 along the lines 206, so that individual stacks are formed, with the transfer adhesive exchanged between opposite edges of the stack. The resulting stack can then be further trimmed along the direction perpendicular to the desired stack size and shape (Figure 14c).

Although the above description applies to sheets such as paper, they could be done (as it already was

-19 mentioned) from other materials, such as polymer films, as previously described. When the sheets are paper, they are preferably fed through a machine having a " machine direction of sheets of paper, aligned with the direction of the machine process; in this way, the tendency of the leaves to twist or crush may continue to decrease.

Papers of different weights and textures can be used if desired. For example, the described device is readily adaptable for processing, for example, A4 size sheets or A2 size sheets. Similarly, the device is capable of processing sheets of relatively high weight (e.g. 250 g / m ² ) as well as sheets of lower weight (e.g. 80 g / m ² ).

If the sheets fed to the dual coating preparation 3 are preprinted, the result of the procedure described above is that the LAB coating material is applied over the printed matter on the sheets. The LAB coating is then used to protect the printed matter, especially against adhesive removal on the adjacent sheet when the sheets are later stacked and cut to form blocks of removable sheets. The protection provided by the LAB coating allows the use of stronger adhesives on printed matter. Of course, the printed matter can also be applied to sheets on a dual coater 3, whether pre-printed or not, using any conventional printing operation.

Although the sheet removal preparation of Figure 10a has been described above as an integral part of the adhesive coating preparation, it will be understood that it could be used in other circumstances when required to apply coating material to the sheets using infinite transfer .

It will also be understood that various modifications may be made to the overall configuration of the apparatus shown in Figure 1 without affecting the operation of the adhesive coating device 7 (and in particular the sheet removal apparatus). For example, the cover station 4 could be omitted and the sheets could be fed directly from the double coating device 3 to the dryer. In this case, the sheets could overlap just before being fed into the adhesive coating device 7. Such an arrangement is described in our patent application GB Serial no. 9603281.8, filed 2/16/96 and entitled Method and apparatus for coating sheets on both sides with water-based material (= Method and apparatus for coating sheets on both sides with water-based material), which also describes how sheets from the dryer may be they are collected and folded and subsequently re-fed as a pseudo-set of covered sheets to the adhesive preparation.

-20Furthermore, although it is desirable, it is not essential that the sheets be fed to the double coated preparation in the uncoated state. For example, it could be fed into and through a dual coating preparation as a pseudo-set of coated sheets, as described in WO 94/19419 above. Station 4 for covering the sheets of Figure 1 (including the device of Figure 8 for changing the direction of coverage) is not required in this case.

Claims (12)

PATENT APPLICATIONS A stack of flexible sheet material comprising a large number of sheets arranged on top of each other, each sheet having a removable adhesive along one edge and without adhesive along the opposite edge, and the sheets being stacked with a removable adhesive of each sheet arranged along alternating opposite edges to keep the leaves in line, characterized in that at least two of the leaves of said large number of leaves are different from each other. 2. A fund as claimed in claim 1, wherein said stack comprises a majority of sheets that are similar and one or more sheets that are different from said majority of sheets and which are inserted into said stack. 3. A fund according to claim 1, wherein said fund comprises similar first leaves and similar second leaves, said first and second leaves being different and exchanging within said fund. A fund according to any one of the preceding claims, wherein at least two sheets in said fund are different in color and / or print. A stack according to any one of the preceding claims, wherein each sheet in said stack has a removable adhesive along one edge in the form of a strip or in the form of spots A fund according to any one of the preceding claims, wherein all the sheets in said stack are of paper. A dispensing device comprising a stack of sheets as defined in any one of claims 1 to 6, wherein said dispensing device has accessories for the walls surrounding the stack, including an upper wall with a transverse opening through which the part extends at the edge without adhesives of the highest sheet in accordance. 8. A process for applying removable adhesive to sheets, comprising the steps of: (a) applying a removable adhesive to an endless transfer surface; -22 (b) transporting a large number of sheets, at least two sheets of which are different from one another, in an end-to-end overlapping connection to the transfer location; and (c) contacting the sheets at the transfer site with the transfer surface to transfer the removable adhesive to the sheets, thereby obtaining a coated surface on each of said sheets; wherein said removable adhesive is applied to said infinite transfer surface such that when the removable adhesive is transferred to the first and second sheets closest to each other, the coated surfaces on said first and second sheets are displaced relative to each other in a rectangular manner directions to the direction of leaf transport, 9. A device for applying removable adhesive to a large number of sheets, the device including a transport device for transporting a large number of sheets in an end-to-end covered connection to the transfer location; an endless transfer surface that moves through the transfer location in contact with the transported leaves; and a coating agent adapted for applying the removable adhesive to an endless transfer surface for later transfer to the sheets to form coated surfaces in these at the transfer site; said coating agent being capable of applying a removable adhesive to said transverse transfer surface such that when the removable adhesive is transferred to the first and second sheets closest to each other, the coated surfaces on said first and second sheets are offset the other relative to the other in a perpendicular direction to the direction of leaf transport. The apparatus of claim 9, wherein said coating means comprises an engraving roller having a first and second engraving extending about a portion of the circumference of the engraving roller and said first and second engravings being radially and axially displaced relative to each other . -2311. The apparatus of claim 10, wherein said first and / or second engravings are in the form of a belt, circle or ellipse. 12. The apparatus of claim 9, wherein said endless surface for transferring the synchronization means. 13. The device of claim 9, wherein said device further comprises: a separation conveyor located just along the line of leaves leaving the transfer station; and a low pressure source usable for application over the first portion of the separation conveyor length closest to the transfer station, first level reduced pressure sufficient to separate the sheets from the transfer surface and to draw the sheets to the separation conveyor, and above to other parts of the length of the tape, of a reduced pressure at the second level, sufficient to keep the sheets on the separation conveyor to be removed from the transfer station.