It is known in the art to provide a laminating machine for laminating objects such as written or printed material such as paper or card, using a plastics material cover. Such a cover is generally formed from a single piece of plastics material, for example, clear PVC, which is folded along a centreline, leaving three open edges, thus forming a cover over the object to be laminated. The written or printed material is then placed inside the cover and the cover is fed through a laminating machine. The laminating machine heats the plastics material, thus sealing the three open edges and ensuring close contact between the cover material and the written or printed material, to give a professional finish. In this way the written or printed material is protected from damage by substances and from tears and folds as well as from security tampering. This is particularly useful for items such as menus and identity cards.

One known type of laminating machine suitable for producing the above-described items in this way comprises a pair of heated cylindrical rollers disposed a suitable distance apart forming a throughput slit so that an object and cover is held between the two rollers and can be sufficiently heated for the sealing process to occur. Both rollers rotate about their central axes such that an object and cover can be fed between them to achieve the desired sealing effect. This type of machine also comprises a motor for rotating the rollers and means for heating the rollers. There may also be provided a simple feed tray in which objects to be laminated in their covers are placed, for assisting the feeding thereof.

One factor to consider when using the above-mentioned type of laminating machine is that it can be difficult to correctly align and feed the objects and covers.

The simple feed tray assists somewhat in feeding the objects and covers to the laminating rollers, but there is nevertheless a requirement for an operator to carefully align the objects and covers. Furthermore, this must be done for each

object and cover. It would be desirable to provide a laminating machine which mitigates these problems.

The applicants have described a so-called"vertical laminator in International Patent Application No. PCT/EP00/06323, the contents of which are herein incorporated by reference.

According to the present invention, there is provided a laminating device for laminating a cover onto an object, the device comprising a pair of laminating rollers arranged to rotate at a first speed; and a feeder roller disposed at a distance from the pair of laminating rollers and arranged to rotate at a second speed, which is less than the first speed, to supply the object and cover to the pair of laminating rollers, such that when the object and cover are received by the pair of laminating rollers, the difference in speed ensures they remain tensioned.

Preferably the laminating device comprises a pressure plate arranged to co- operate with the feeder roller for supplying the object and cover to the pair of laminating rollers. Conveniently, the laminating device comprises a spring arrangement which is operable to spring-load the pressure plate towards the feeder roller so that the object and cover are firmly held between the two and supplied in a steady manner.

A suitable structure for the feeder roller is a driven core roller and one or more outer rollers disposed around the core roller and extending along a part of the length of the core roller, the outer rollers being provided for co-operating with the pressure plate so as to allow an object and cover to be aligned between the feeder roller and the pressure plate. Such a core roller is driveable by a first motor via a free wheel drive and the pair of laminating rollers is driveable by a second motor, wherein a tension on the free wheel drive stops the first motor to prevent further rotation of the core roller, the second motor continuing to drive the pair of laminating rollers and draw the object and cover between the pair of laminating rollers.

Advantageously there is also provided a feeder support member in which one or more objects and their covers can be placed, wherein under no tension, the first motor causes rotation of the feed roller, thus drawing a second object and cover between the feed roller and the pressure plate, the slower speed of the feed roller ensuring that the second object and cover do not foul with the first object and cover.

Preferably the resting position of the pressure plate is spring-loaded away from the feeder roller, and this resting position allows the placement of one or more objects with their covers in the feeder support member, the laminating device further comprising activation means for starting the first motor, and wherein the spring arrangement is operably linked to the first motor so that starting the first motor causes the spring arrangement to spring-load the pressure plate towards the feeder roller. The activation means may be further arranged to start the second motor.

A laminating device in accordance with the invention may also comprise a heating device for heating the laminating rollers. Preferably a sensor for detecting a temperature of the laminating rollers is provided, which, when that temperature reaches a pre-determined minimum value, activates an indication of that fact. The indication may be a visual indication or an audible indication. Advantageously, before the temperature has reached the predetermined value, the activation means is overridden for preventing starting of the first motor, but after the temperature has reached the predetermined value, the activation means is activatable. The activation means may be a button operable by a user or a switch which is responsive to the indication of the temperature reaching the pre- determined minimum value to automatically start the first motor.

Conveniently, the laminating device comprises a temperature control device for controlling the heating device in dependence on the temperature of the surface of the laminating rollers, to maintain the temperature at or just above the predetermined minimum temperature. It may depend on the temperature of another part of the laminating rollers.

The laminating device may comprise a collecting tray for collecting laminated objects emerging from the pair of laminating rollers.

The laminating device may be a vertical laminating device or may operate at a differentangle.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a perspective view from the front, top and left side of a feeder unit which forms part of a laminating device; Figure 2 shows a perspective view from the rear, top and left side of the feeder unit of figure 1; Figure 3 shows a plan view of part of a laminating device; Figure 4 shows two views of a free wheel drive suitable for use in the feeder unit of figure 1; and Figure 5 shows a diagrammatic side view of the major components of a laminating machine of the invention.

In the figures, like reference numerals indicate like parts.

Referring firstly to Figure 1, there is shown a feeder unit, indicated generally by reference numeral 1. Use of the feeder unit within a laminating machine will be explained more fully below with reference to other figures, but its purpose is to provide a reliable way of passing an object and its cover to a pair of laminating rollers. The following paragraphs will describe the main components of the feeder unit 1, but it should be understood that there may be other components which allow the feeder unit 1 to function as described.

The feeder unit 1 comprises a support base 2, which has a main rectangular section base plate 4, and three side plates disposed at right angles to the base plate 4, which run across the full width of the base plate 4. Left side plate 6 and right side plate 8 are disposed at opposite ends along the length of base plate 4, and central plate 10 is disposed offset along the length of base plate 4 towards

right side plate 8. The area formed by left side plate 6 and central plate 10 is the area in which an object and cover can pass through in use. It would be possible to allow central plate 10 to be moveable along the length of base plate 4, thus allowing differently sized objects and covers to be accommodated.

Two sets of aligned holes are provided in plates 6,8,10, such that two shafts can rotate freely about axes aligned along the length of base plate 4. One set of aligned holes is provided towards the front of the support base 2 as shown in figure 1, and a first shaft 12 rotates in these holes : This shaft 12 supports a base plate which comprises two plate parts. The first plate part 14 is attached proximate to left side plate 6 and the second plate part 16 is attached proximate to central plate 10. The plate parts 14,16 extend from the shaft 12 across substantially the entire width of base plate 4. Each extends along approximately a quarter of the distance between left side plate 6 and central plate 10. They are fixedly attached to the shaft 12 so that they rotate with it. The shaft 12 extends out of the left hand side of left plate 6, so that a spring arrangement 18 is attached to the shaft 12 on the left hand side of left plate 6, i. e. outside the area formed by left side plate 6 and central plate 10 in which an object and cover can pass through in use. The shaft 12, the plate parts 14,16 and the spring arrangement 18 form a pressure plate.

The other set of aligned holes is provided towards the rear of the support base 2 as shown in Figure 1, and a second shaft 20 rotates in these holes. The shaft 20 supports two outer rollers which are substantially cylindrical in shape and have a central hole running along their length with a diameter corresponding to the diameter of shaft 20 so that they fit thereon. The first outer roller 22 is attached proximate to left side plate 6 and the second outer roller 24 is attached proximate to central plate 10. Each roller 22,24 extends along approximately a quarter of the distance between left side plate 6 and central plate 10, and hence corresponds to the plate parts 14, 16 respectively. They are fixedly attached to the shaft 20 so that they rotate with it. the shaft 20 and te outer rollers 22, 24 form a feeder roller.

Shaft 20 extends out of the left hand side of left plate 6, so that the feeder roller can be provided with a free wheel drive 26 attached to the shaft 20 on the left hand side of left plate 6, i. e. outside the area formed by left side plate 6 and central plate 10 in which an object and cover can pass through in use. The spring arrangement 18 is also connected to shaft 20, for reasons which will be explained below.

It will be appreciated that the relative dimensions of the components of the feeder unit 1 can be varied within the scope of the invention. The distance from base plate 4 in the perpendicular direction of plates 6,8,10 at which holes are formed to allow shafts 12,20 to rotate will be chosen as appropriate for the pressure plate and the feeder roller to interact as described below. It is likely that the feeder unit 1 will be provided with a cover, but this is not shown in Figure 1, so that the above- mentioned components can be seen.

Figure 1 shows the feeder unit 1 in its rest position, i. e. when an object and cover are not being fed by it. The spring arrangement 18 naturally biases the pressure plate away from the feeder roller, so that the plate parts 14,16 are not in contact with the outer rollers 22,24. This enables insertion of an object and cover in the direction shown by arrow A. The correct straight insertion of an object and cover is facilitated by the side plate 6 and the central plate 10.

Referring now to Figure 2, this shows the feeder unit 1 in a rear perspective view.

From this angle, two stops can be more clearly seen. Stop 28 is attached to base plate 4 in a corner area of base plate 4 formed with left side plate 6 at the rear of feeder unit 1 and extends for approximately a quarter of the distance between left side plate 6 and central plate 10. Stop 30 is attached to base plate 4 in a corner area of base plate 4 formed with central plate 10 at the rear of feeder unit 1 and extends for approximately a quarter of the distance between central plate 10 and left side plate 6. Due to their positioning and dimensions, stops 28,30 co-operate in the rest position with outer rollers 22,24 respectively to prevent an object and cover from falling completely through the feeder unit 1 from the front to the rear when inserted in the direction of arrow A. This is particularly important when the feeder unit 1 is used in a vertical configuration.

In operation, under the action of either a button, or perhaps a switch (as discussed below), spring unit 18 operates to spring-load the pressure plate towards the feeder roller. This means that an object and cover which have been inserted in the direction of arrow A to come to rest against stops 28,30 are pushed towards outer rollers 22,24 and held firmly in place between them and plate parts 14,16.

They are simultaneously lifted sufficiently to be able to clear stops 28,30 so that when shaft 20 is rotated, the object and cover will be fed over stops 28,30 and out of feeder unit 1. Shaft 20 is rotated by means of a first motor 27, which is not shown in Figure 1, but can be seen in Figure 3 described below. As shaft 20 is rotated in the direction shown by arrow x, the object and cover are moved out of the feeder unit 1 as indicated by arrow B. Due to the guiding ability of side plate 6 and central plate 10 and the spring action of the pressure plate against the feed roller holding the object and cover firmly gripped, they are fed out of the feeder unit 1 in a controlled manner with respect to speed and direction. Thus this is an improvement over prior art systems which often do not incorporate a reliable way of feeding objects and their covers.

Turning now to Figure 3, which shows a front view of some components of a vertical laminating machine 40, the feeder unit is indicated generally by reference numeral 1 as in Figure 1, and the visible components of the feeder unit 1 are labelled. Note that the first motor (which drives the feeder roller) is shown indicated by reference numeral 27.

Upstream (using the same positional and directional references of arrows A and B of Figures 1 and 2) of the feeder unit 1, is provided a feeder tray 32, filled with several objects in their covers, indicated generally by reference numeral 34. Two objects and their covers are particularly shown and indicated, 34a being passed through the laminating machine, and 34b being the next one, waiting against stops 28,30.

Downstream of feeder unit 1 is a pair of laminating rollers 50, driven on central shafts 52. Only the front roller 50a and its shaft 52a are visible in Figure 3, since the second roller 50b is disposed behind roller 50a (into the page), forming a

throughput slit between the two. Laminating rollers 50 are driven by a second motor 54. They are heated electrically by a circuit shown diagrammatically as comprising a power supply 56 and a control circuit 58. They are formed of a suitable material which converts electrical energy into heat, or alternatively they can be heated by a special outer plate as described in the applicant's UK Patent Application No 0018605.6, or heated internally as described in the applicant's German Patent Application No. 199613656. The details of the heating circuit can be varied as appropriate for the method of heating chosen. The purpose of the control circuit 58 is to allow an indication to be made that the rollers 50 have reached the correct temperature for laminating and to maintain the rollers 50 at or just above that temperature. The details of such a temperature regulation circuit could vary within several known methods, one example being a proportional- integral (Pi) controller circuit. The circuit is used in conjunction with a suitable temperature measurement device on the rollers, such as a thermistor. A suitable range of operating temperature for the laminating rollers 50 is 85-160 degrees Centigrade.

In operation, the pair of laminating rollers 50 is heated by virtue of the power supply 56 until they reach a predetermined temperature (this may be gauged against their surface temperature, depending on the method of heating). At this point, the control circuit provides an indication that the laminating rollers 50 are ready to laminate a cover onto an object. This may take the form of a visual or audible indication to an operator, or any other suitable form.

When the indication has been received, the laminating machine is put into operation. Depending on the sophistication of the machine, which in turn will depend on its intended use, either a button can be provided or an automatic switch, which performs the function of starting motor 27 to cause rotation of shaft 20 via free wheel drive 26. Due to spring arrangement 18 being connected to shaft 20, this rotation causes the pressure plate to be spring-loaded towards the feeder roller. This results in an object and cover sitting on stops 28,30 being fed through feeder unit 1 to emerge in a controlled manner in the direction of arrow B, as described above with reference to Figures 1 and 2.

When the object and cover emerge from feeder unit 1, they continue to be fed so that they arrive at the pair of laminating rollers 50. The rollers are situated with respect to the feeder unit 1 so that the object and cover are fed into the throughput slit formed between the rollers 50. As they pass through the rollers 50 the cover is laminated onto the object under the heat of the rollers, so as to form a laminated object. Object and cover 34a are shown at the stage where most of their length has emerged from the feeder roller and some of it has also emerged from the laminating rollers 50, there being the remainder of the length left to pass between the feeder roller and the pressure plate.

The operation of motor 54 driving laminating rollers 50 can be controlled in two ways. It can be started at the same time as motor 27 using, either the same starting means as for motor 54 or, for example, a separate switch or button provided on the device and can be left running continuously during use of the machine. More preferably a sensor can be provided on the buffer feeder so that the motor 54 is stopped for example after a time delay following a lack of detection of an object and cover between the rollers. In this case, an operator could allow a short delay in putting more objects and covers into the buffer feeder, but after a longer delay, power would be saved by automatic stopping of the motor.

The second object and cover 34b is shown still waiting in the feed tray 32 but partially sitting in the feeder unit 1 so that they are stopped from falling any further by stops 28,30 (not visible in figure 3). The exit from the feeder tray 32 and the entrance to feeder unit 1 are so designed (and may be adjustable for differently sized objects) so that only one object and cover can fall to the position of 34b at any one time, thus ensuring that only one is fed between the feeder roller and pressure plate at once.

An important feature of the laminating machine is that the pair of rollers 50 rotates at a slightly higher speed than the feeder roller. This is so that as soon as an object and cover are taken up by the rollers 50 they are maintained in tension due to the difference in speed. This ensures a smooth feeding through the laminating rollers 50 and hence a good quality of lamination.

The difference in speed causes a further effect, which is that the free wheel drive 26 prevents further rotation of shaft 20. Before an object and cover 34 arrives at laminating rollers 50, shaft 20 is driven, via free wheel drive 26 in its transmission mode. However, when the object and cover 34 are put under tension by the higher speed of the laminating rollers 5Q, this causes the free wheel drive to change to its freewheeling mode, and hence prevent rotation of shaft 50. The operation of the freewheel drive 26 will now be explained in greater detail, with reference to figure 4.

Figure 4a shows a cross-section through a freewheel drive suitable for use as freewheel drive 26, in its transmission mode. It has a cylindrical sleeve 60 containing a cylindrical roller guide ring 62 on its inner surface. Within the roller guide ring 62 is a ratchet 64 provided with five drive rollers 66. The ratchet 64 is nominally cylindrical, so that it is able to rotate about its central axis in the direction of arrow z. However, the outer surface of ratchet 64 is provided with five cut-out grooves 68, in each of which a drive roller 66 sits. The depth of the grooves 68, and hence the width of the gap between the ratchet 64 and the roller guide ring 62, varies within each groove, around the circumference of the ratchet 64. The width of gap affects whether or not the drive rollers 66 fit comfortably in the grooves 68. In figure 4a, the drive rollers 66 are situated in a part of the grooves 68 in which the width of the gap jams the drive rollers 66 against the roller guide ring 62, thus transmitting the power from motor 27 to drive shaft 20 via sleeve 60. In Figure 4b, the drive rollers 66 have moved into a depression in the grooves 68, and are no longer jammed against sleeve 60, due to the greater width of the gap at this point.

This means that it is not possible to transmit power to the sleeve 60, but instead the sleeve 60 is able to freewheel. It will be understood that the number of grooves and drive rollers is not limited to five. Furthermore, the design of the freewheel drive is not limited to the one shown in the figure. Any suitable freewheel drive can be used.

In operation in the laminating machine 40, when an object and cover are initially being fed through feeder roller, the freewheel drive is operating as in Figure 4a, so that power is transmitted to shaft 20, causing it to rotate. When the object and cover arrive at laminating rollers 50 and the higher speed of these rollers puts the

object and cover under tension, this causes the tension force to be transferred to the freewheel drive 26, and this causes the drive rollers 66 to be released into the positions of figure 4b, and hence no power is transmitted to shaft 20 and it stops rotating. One advantage of this is that it is not possible for the next object and cover to be taken up by the pressure plate and outer rollers 22,24, which means that the object and cover currently passing through the laminating rollers 50 can be fully discharged from the feeder roller without being fouled by the next object and cover. This in turn means that no fouling occurs within the laminating rollers 50. As soon as that object and cover are fully discharged from between the feeder roller and pressure plate, the tension force is removed, and therefore the drive rollers 66 can return to the positions of Figure 4a, and allow power to be transmitted to shaft 20. At this stage, the next object and cover can be taken up by the feeder roller and pressure plate and fed on to laminating rollers 50.

Spring arrangement 18 is connected to shaft 20, as explained above with reference to Figure 1. When shaft 20 is prevented from further rotation as described above, the spring arrangement 18 releases the base plate shaft 12, such that plate parts 14,16 are no longer sprung against outer rollers 22,24. The laminating rollers 50 have sufficient control over the object and cover at this stage. This means that the next object and cover can fall down to the position of object and cover 34b in figure 3, i. e. prevented from falling any further by stops 28,30.

When shaft 20 re-starts as described above, spring arrangement 18 then springs plate parts 14,16 against outer rollers 22,24 again, thus taking up the next object and cover to a position for being fed through the feeder roller. The feed tray 32 is designed so that only one object and cover can fall down against stops 28,30 at any one time, and not when the pressure plate is sprung against the feeder roller.

Figure 5 shows diagrammatically a side view of the arrangement of Figure 3, in which object and cover 34a is in a similar position to its position shown in Figure 3 and object and cover 34b are just about to fall down against stops 28,30 in preparation for being fed through the feeder roller. Both laminating rollers, 50a and 50b can be seen in this view. There is further shown a collector tray 70. This can be of a particular design which allows advantageous collection of a number of

laminated objects, as described in the applicant's International Patent Application No. PCT/EP00/06323.

It will be understood that the figures do not show the only dimensional arrangement of components but that the relative sizes and spacing of components can be varied within the scope of the invention. It may be desirable to provide a second pair of laminating rollers downstream of the pair of rollers 50, to provide a better quality of lamination. The decision will depend on the proposed use of the machine and the quality of laminated objects which it needs to produce. Furthermore, whilst a vertical laminating machine is shown in the figures, the invention is equally applicable to a laminating machine set at a different angle.