BACKGROUND OF THE INVENTION AND PRIOR ART Thermal transfer printers in particular are nowadays in widespread use in the printing and packaging industries.

The high speed printing of labels using such apparatus is particularly common. However, presently used apparatuses which involve the winding of material such as printing ribbon or foil from one spool or reel to another all necessitate a certain amount of stop or down time when an empty spool or reel has to be replaced with a new, full one. This can be a common problem as regards the efficiency of the winding process, with knock-on effects as regards the economics of an overall printing or manufacturing process which employs such winding apparatus.

A similar problem arises in the related field of packaging, in which labels carried on a backing tape are applied at high speeds to products or their packaging.

The problem has been addressed to a certain extent in the known art by the use of cassettes preloaded with the material, which are ready for manual changeover as soon as the material has been used up. Although this ameliorates to some extent the problem of deleterious stop times associated with conventional spools or reels, the problem usually still remains that some amount of stop time upon changeover of cassettes is necessary.

It is an object of the present invention to further ameliorate the above problem and to provide winding apparatus which includes a changeover device for replacing an exhausted spool or reel with a new, full one which involves minimal or preferably even no stop-or downtime in the overall winding process and which preferably enables changeover of reels to be accomplished automatically without manual intervention or assistance.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a material winding apparatus for transferring flexible material from an input reel at an input reel position to an output reel at an output reel position via a winding path, the apparatus including a changeover device for replacing an empty input reel mounted at the input reel position with a full replacement reel of the flexible material when transfer of the material from the input reel to the output reel is substantially complete, wherein the changeover device comprises: support means carrying first reel mounting means at the input reel position, second reel mounting means at the output reel position and at least one auxiliary reel mounting means located at a or a respective replacement reel position displaced from both the input and the output reel positions, the support means including drive means for moving the input, output and replacement reels between

their respective positions; and control means for determining when an input reel at the input reel position is empty or near-empty, and/or when an output reel at the output reel position is full or near- full, and in response thereto causing the drive means to move the first, second and auxiliary reel mounting means between their respective positions such as to bring an empty input reel into the output reel position, a full output reel into a replacement reel position and a full replacement reel into the input reel position.

As used herein, the term"reel"is to be construed in a broad sense as encompassing all sorts of reel, spool, winding core and other like winding devices upon or from which flexible material can be wound or unwound by rotation of the device about its central axis.

Furthermore, the invention is applicable to a wide variety of such flexible materials that in various technical applications are wound or unwound onto or from various kinds of winding device as mentioned above.

Typically such flexible material is in the form of tape, ribbon, foil or a wide variety of filamentary materials, but the invention may also be applied to the winding of other kinds of material in lengthy web form.

The invention is also applicable for example to apparatus for the winding, during use, oi multi-layer (e. g two-layer) web materials, such as twin till rolls of paper used in cash registers. In such apparatus there is a simultaneous winding (or rewinding) of one of the paper layers with unwinding of itself and one or more of the other layer (s). The plurality of layers of such multi-layer materials by be continuous (as is the case with twin till rolls) or non-continuous (as is the case with labels carried on a backing material).

In one particularly preferred form of the apparatus of the invention, the support means is rotatable about a central axis and a single auxiliary reel mounting means is provided at a single replacement reel position rotationally displaced from the input and output reel positions. When actuated, the drive means of the apparatus causes rotation of the support means so as to bring the empty input reel, the full output reel and the single full replacement reel into their new positions. Thus, the movement of the various reels from their existing into their new positions is achieved by rotation of the support means carrying them by the appropriate angular distance.

The invention is not limited, however, to the case where just three reels (i. e. input, output and single replacement reels) are involved and it is possible within the scope of the invention for there to be a plurality of replacement reels provided in respective auxiliary replacement reel positions on the support means. Movement of the various reels between their respective positions, i. e. a full replacement reel into the input reel position, an empty input reel into the output reel position, and a full output reel into a replacement reel position (which is different from the replacement reel position that the aforementioned full replacement reel finds itself immediately before the changeover movement takes place), is achieved by appropriate angular movement of the support means.

However, in a second preferred form of the invention, the movement of the above described various reel mounting means is achieved not by rotation of the support means carrying them, but by translational movement around a reel- movement path. This path may take any suitable desired configuration, e. g. rectangular, pentagonal, hexagonal, (e. g. dependent on the number of reels) with each side of the path being either straight or curved. This alternative

movement of the various reels may be accomplished by any suitable drive means of the nature of an actuator or transfer mechanical mechanism. Specific examples of such suitable mechanical transfer means are to be found in the existing art and will therefore be readily available to the skilled person for inclusion in such apparatus according to this alternative family of embodiments of the present invention. Implementation of the invention according to this alternative form of embodiment may be particularly useful in the case where more than three reels are employed, i. e. where there are two or more (e. g. three, four, five or even six or more) replacement reels provided at respective ones of a plurality of auxiliary reel mounting positions on the support means of the apparatus.

In practical embodiments of the invention means are preferably provided for automatically starting the unwinding of material from the full replacement reel around the winding path once it is brought into the input reel position, so that there is essentially no discontinuity in the unwound material as the empty input reel is exhausted and replaced with the full new one. A preferred example of such means for accomplishing this comprise a self-adhesive layer provided at or near the end portion of the material to be unwound from the first input reel. This self- adhesive portion adheres itself to and picks up a start portion at the beginning of the material to be unwound from the full replacement reel. This pick-up step may be assisted by a suitable pressure-applying pick-up element mounted in the apparatus adjacent the input reel position.

Also in practical embodiments of the invention cutter means are preferably provided adjacent the displaced full output reel to sever the material once winding of it on the full output reel is complete and once winding of material onto the new, empty reel brought into the output reel position from the input reel position has begun.

Furthermore, in practical embodiments of the invention means are preferably provided to automatically start winding of material onto the new, empty output reel once it is brought into the output reel position from its previous input reel position. Such means may comprise a self- adhesive surface on the core of the empty reel, which may be the surface of the core itself or alternatively an opposite surface of the same self-adhesive portion of the end region of the material unwound from the input reel as mentioned above.

As an alternative to adhesive, for the above mentioned application, any other suitable bonding means may be employed, however.

In preferred embodiments of the invention the control means for determining when an input reel at the input reel position is empty or near-empty, and/or when an output reel at the output reel position is full or near-full comprises sensor means for automatically sensing when such a condition is reached, and signal means for passing a signal to the drive means to cause the movement of the various reel mounting means by the required amount. Alternatively, the control means may have previously had input to it precalculated information concerning the point at which changeover of the input reels is required, and react accordingly to that input data to actuate the drive means at the required time.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Further preferred features of the invention will be described further below in the context of a detailed description of preferred embodiments of the apparatus of the invention, with reference to the accompanying drawings, in which: Figure 1 is a schematic plan view of the apparatus of

a first preferred embodiment showing the condition in which an input reel is approaching empty and an output reel approaching full; Figure 2 is a schematic plan view of the apparatus of Figure 1 immediately after the support means has been rotated and the relative positioning of the reels shifted so as to bring into play a new, full, replacement input reel of material; Figure 3 is a schematic plan view of the apparatus showing its condition a short time after that shown in Figure 2, in which unwinding of material from the new input reel is about to begin and the material having now been fully wound on the now displaced output reel about to be severed ready for beginning its winding on to the new, empty output reel; Figure 4 is a schematic plan view of the apparatus of a second preferred embodiment of the invention illustrating the apparatus in a corresponding stage in its operation as shown in Figure 2 in the context of the first preferred embodiment.

Referring firstly to Figure 1, here there is shown the material winding apparatus of the first preferred embodiment which typically forms part of a larger apparatus such as some form of printing machine. For example, the flexible material 5 being transferred from the input reel 2 to the output reel 3 of the apparatus may be a thermal transfer printing ribbon or foil used in the printing of some other product or it may be in the form of a backing tape comprising adhesive labels which are to be printed by the machine. Alternatively, the apparatus may form part of a label application apparatus, in which the material unwound from the input reel 2 comprises printed labels on a backing tape, but the material wound onto the output reel 3 is just the remnant backing tape after the labels have been applied to products at a point somewhere along the winding path 7,8,9,10,11 between the input and output reels 2,

3. In all cases only the essential and otherwise important features of the winding apparatus of the present invention are actually shown in the drawings, remaining components of the overall machine or apparatus being omitted for clarity but being well known and understood by persons skilled in the art.

The winding apparatus as illustrated in Figure 1 comprises a support plate 4 which is rotatable about a central axle or axis 15. The support plate 4 carries on its upper surface mounting means for each of input reel 2, output reel 3 and replacement reel 1. Flexible material 5 which was initially wound on a full input reel 2 moves along a winding path represented by rollers 7,8,9,10 and 11 before arriving at output reel 3 upon which it is wound after fulfilling its function, examples of which in the context of various possible types of flexible material are discussed above. In the condition of the apparatus illustrated in Figure 1, the flexible material 5 has been almost completely unwound from input reel 2 which is therefore nearly empty, output reel 3 being correspondingly nearly full. (In alternative embodiments the support plate 4 may take the form of a frame or any other assembly suitable for the purpose and carrying the various reel mounting means.) The mounting means by which each of the reels 1,2 and 3 is mounted on the support plate 4 may be of any suitable known type. In practical embodiments of the apparatus either or possibly both of input and output reels 2,3 are driven by drive means, which are not shown in the drawing but may be of any suitable known type, e. g. one or more electric motors operated under the control of the overall control system of the apparatus or machine. Also, any one or more of the rollers 7,8,9,10 and 11 defining the winding path of the flexible material 5 may be driven, as is well known in the field of winding apparatuses of

various kinds. In practical embodiments the driving of one or more of the input and output reels and/or rollers of the winding path may for example be chosen to provide a desired degree of tension in the flexible material being wound.

In the condition of the apparatus as illustrated in Figure 1 the full replacement reel 1 normally remains stationary, until such time as it is brought into the input reel position to replace the empty input reel 2, as will now be described with particular reference to Figure 2.

The changeover mechanism which substitutes the empty input reel 2 for the full replacement reel 1 is actuated preferably automatically once it has been determined that the input reel 2 is empty or nearly empty. This determining may advantageously, and indeed preferably, be done by sensor means which monitors the state of unwinding of the input reel 2 and provides an output signal when the input reel 2 reaches a predetermined state of unwinding.

Such sensor means may for example be based on optical sensing, or any other suitable detection mechanism as will already be known in the art or related arts for fulfilling the same or similar function. Such sensor means are not illustrated in the drawings, but their construction, operation and positioning will be readily appreciated and understood by persons skilled in the art. An alternative way of determining when the input reel 2 is empty or nearly empty is by precalculating when that is due to occur, which can be readily done with knowledge of the amount of material on the full input reel at the start and its rate of unwinding. The overall control system of the apparatus can then be programmed with that precalculated data and the control means actuated at the appropriate time to operate the changeover mechanism.

As an alternative to determining when the input reel 2 is empty or nearly empty, it is of course possible to

determine the corresponding situation where the output reel 3 is full or nearly full.

When it has been determined that all or substantially all of the material 5 has been transferred from the input reel 2 to the output reel 3 the control means actuates the changeover mechanism which comprises primarily drive means (not shown) which rotates the support plate 4 in an anticlockwise direction (as shown in the drawings) until the empty input reel 2 is brought into the output reel position previously occupied by output reel 3, the output reel 3 is brought into the replacement reel position previously occupied by replacement reel 1, and replacement reel 1 is brought into the input reel position previously occupied by input reel 2. In the preferred embodiment of the apparatus the input, output and replacement reel positions defined by the location of the respective mounting means for each reel are located radially equidistant from the axle 15 about which the support plate 4 rotates, with the axes of rotation of the three reels being disposed equiangularly around the circumference of an imaginary circle corresponding to that radius. In other words, the replacement reel is rotationally displaced from both the input and the output reel positions. As a result of this arrangement, a 120° anticlockwise rotation of the support plate 4 moves the three reels from the position shown in Figure 1 to that shown in Figure 2.

The rotation of the support plate 4 may be achieved by any suitable drive means such as an electric motor or even an electromagnetically operated mechanism, practical examples of which are readily available. Such drive means may or may not be part of an overall integrated drive system for any or all rotating components of the apparatus. Moreover, overall control of all the various drive means is preferably achieved by an integrated electronic control system, as will typically be the case with known

apparatuses of the type with which the preferred embodiment of the invention is concerned.

Returning to Figure 2, once the shifting of the three reels into their new positions has occurred, it is preferred that unwinding of material 5 from the new, full input reel 1 and its winding onto the new, empty output reel 2 via the winding path 7,8,9,10,11 continues without a break, without the winding operation stopping or otherwise being interrupted from its normal rate. It is possible, however, that the rate of winding may for instance be temporarily slowed while the changeover of reels is completed.

As the full replacement reel 1 is brought into the input reel position, drive means (if present) which previously drove the input reel 2 act on the new input reel 1, so that this becomes the driven input reel from which material 5 is to be unwound. Similarly, as empty input reel 2 is brought into the output reel position, drive means (if present) which previously drove the output reel 3 cease doing so, so that the output reel 3 when brought into the replacement reel position as shown in Figure 2 ceases to be driven. Instead, the drive means (if present) which previously drove the output reel 3 now act on the new output reel 2, which in the presently illustrated case will drive the new output reel 2 in the reverse direction from that in which it was driven when in its previous input reel position. Thus, material 5 is now unwound from new input reel 1 and wound onto new output reel 2 via the same winding path 7,8,9,10 and 11 in an exactly corresponding manner to the case of the former input reel 2 and output reel 3 as illustrated in Figure 1.

A terminal section 13 of the material 5 which is the last to be unwound from original input reel 2 is provided, e. g. coated with, a layer of self-adhesive material on its

side which passes against the outer winding of material 5 on the outside of new input reel 1 as it is drawn therepast. The bonding force of the adhesive on this terminal section 13 of the material 5 is designed so as to adhere to and thereby pick up the terminal end portion of the material 5 on the new input reel 1, with the result that the respective terminal end portions of the two lengths of material securely adhere together so as to form an effectively continuous join between the two lengths.

Thus, the material continues around the winding path unbroken. Suitable adhesives for this purpose are well- known and readily available commercially. The bonding together of the terminal end portions of both lengths of material 5 is preferably assisted by pressure roller or blade 6 which is mounted in the apparatus so as to apply pressure to the overlapping and adhering terminal end portions of the material as the changeover between reels takes place.

As the above described joining of the terminal end portions of the respective lengths of material 5 is taking place, material from near the end of original input reel 2 is now approaching it in its new output reel position for winding thereon as the new output reel, as shown in Figure 2. The beginning of this output winding action, simultaneous with the picking up by the self-adhesive terminal end portion 13 of the start of the material on the new input reel 1, is shown in Figure 3. To assist the beginning of this winding of material onto the new output reel 2, the surface of the core of the output reel 2 is also provided with a self-adhesive layer, which may for example be the same adhesive material as present on the surface of the terminal end portion 13. The self-adhesive core surface bonds to the material beginning to be wound on it as the new output reel, thereby preventing slippage and causing the beginning of a secure, tight winding.

However, before that new output winding can progress very far, it is necessary for the remnant material at the end of the completed winding on the original output reel 3, which is now in the replacement reel position, to be severed. This is accomplished by cutter 14 as shown in Figure 3. The cutting of the material may be achieved simply by the impacting of the material at a slight angle against the sharp blade of the cutter 14 or possibly the cutter 14 may be designed and operated to advance a short distance in a sliding manner towards the material so as to cut it. Any suitable type of blade or other cutting means may be employed.

Once the severing of the material by cutter 14 has occurred, the former output reel 3 is now free from involvement in the winding process of material from the new input reel 1 to the new output reel 2, leaving it available to be removed from the apparatus and a new, full replacement reel inserted in its place ready for the next time the changeover sequence is actuated. When such a subsequent changeover sequence is desired, exactly the same procedure as described above is repeated. Since now, however, the support plate 4 is already rotationally advanced through an angle of 120° since actuation of the first described changeover sequence, if impact roller/blade 6 is itself mounted on the support plate 4, then corresponding impact rollers/blades 6 (not shown in the drawings) are preferably provided in equivalent locations appropriately rotationally displaced on the support plate 4, in a similar manner to the provision at 120° intervals of the three cutters 14 as are illustrated in the drawings.

Former output reel 3 may be replaced manually at any time during the unwinding of new input reel 1, so that when it comes to the changeover of input reels there is no or substantially no stop or down time of the winding apparatus. If desired the apparatus may include means such

as a magazine which automatically removes reel 3 and replaces it with a new full replacement reel of material ready for the next changeover sequence. The whole mechanism may be automated and actuated under control of the overall control system of the apparatus, which in preferred embodiments will usually be an integrated electronic control system as already mentioned above.

Instead of preapplied adhesive on the terminal end portion 13 of the material 5 and the surface of the core of reel 2, fresh adhesive may be applied automatically and directly to the required locations at the time it is required. Any suitable means for achieving this may be used, as will be readily devisable by persons skilled in the art.

As an alternative to adhesive as the means for joining the two ends of material together, and the free technical end of the material to the empty core, any other suitable bonding means may be employed, for example heat bonding or welding, mechanical joining means such as stapling or any other means operating in a like manner.

In preferred practical embodiments of the above described apparatus according to the invention the control system may include appropriate sensor and alarm means which detect any misfunctioning of the changeover mechanism, for example if the picking up of material from the new input reel 1 or the beginning of the winding of material onto the new output reel 2 fail (s) to take place properly, and upon detection of such an event generate a signal output to actuate local or remote alarm means, e. g. to alert an operator or supervisor of the apparatus or, if desired, to automatically stop the apparatus so that the matter can be rectified. The system can similarly guard against incorrect or incomplete replacement of spent reel 3 with a new replacement reel.

It is to be understood that the above described spatial arrangement of reels in the first preferred embodiment is not essential to the invention and it is possible that more than three reels may be employed in the apparatus, not necessarily in the radially equidistant and equiangular relative positions described above and shown in the drawings. Consequently, the angular rotation of the support plate 4 is selected merely so that upon actuation of the changeover mechanism, the minimum that should happen is that the empty input reel is moved to the output reel position and the new replacement reel is moved into the input reel position.

Referring now to Figure 4, here there is shown schematically an alternative arrangement of, and manner of movement of, the various reels of an alternative apparatus according to a second preferred embodiment of the invention. In this form of the apparatus, there is again provided support means 4', but here it is not of the nature of a rotatable plate, but merely a support plate or frame which carries the various reel mounting means and the associated mechanism by which they are moved translationally between their various positions. As with the first preferred embodiment of the apparatus, flexible material 5'moves around a winding path (defined in an exemplary manner by rollers 9'and 11') from a full input reel 1 to an empty output reel 2. In the particular embodiment illustrated here, three full replacement reels 3,4 and 5 are provided at respective auxiliary reel positions. When the various reels move around the reel- movement path, it is full replacement reel 5 which comes into the position of input reel 1, and into the position of full replacement reel 3 that output reel 2 moves.

Simultaneously replacement reel in the 3 position moves into that in the 4 position, with the latter moving correspondingly into the 5 position.

By use of such a plurality of replacement reels, greater versatility of the apparatus may be achieved, particularly from the point of view of the efficiency of the operation of removing empty reels from the three replacement reel positions and replacing them with full ones for subsequent sequential movement around the reel- movement path as the changeover mechanism operates at each changeover stage.

The various reels are moved in a translational manner around the reel-movement path (which here, by way of example, is rectangular) by known mechanical apparatus provided beneath the support plate or frame 5'or otherwise associated with the support means which defines the reel- movement path. The components and operation of such apparatus are well known and are readily available to persons skilled in the art, so will not be described further here.

The principles of operation of the apparatus of this alternative embodiment illustrated in Figure 4 are essentially the same as those applicable to the first embodiment and described hereinabove in detail.

Corresponding roller means 6'and one or a plurality of appropriately positioned cutter means 14'are also provided, which operate in an analagous manner to those corresponding components of the apparatus according to the first embodiment described in detail above.

Presently preferred embodiments of the apparatus of the present invention have been described herein in detail by way of example only. It is to be understood that various modifications and developments from that which has been specifically described and/or illustrated are possible within the scope of the invention as defined in the appended claims, as will be readily apparent to persons skilled in the art.