WO1995004657A1

WO1995004657A1 - Apparatus for applying heat transferable images

Info

Publication number: WO1995004657A1
Application number: PCT/GB1994/001701
Authority: WO
Inventors: Barry Albert Snowdon; Phillip William Dixon
Original assignee: Checkpoint Security Services Limited
Priority date: 1993-08-04
Filing date: 1994-08-03
Publication date: 1995-02-16
Also published as: ZA945834B; AU7270994A; GB9316154D0

Abstract

Apparatus for applying markings to substrates, particularly documents for authentication purposes, consists of a platen (90, 92) on which the substrate to be marked is located, means for feeding a transfer tape (44) to lie over the platen and a reciprocable heated die (34) adapted to press the transfer tape on to the substrate when it is lying on the platen with sufficient heat and pressure to transfer an image from the transfer tape to the substrate. The tape supply is mounted on a carriage (10, 11) which moves towards and away from the platen, first clamping the substrate against the platen, then bringing the transfer tape adjacent to the substrate and thereafter bringing the heated die into contact with the transfer tape, whereafter the sequence of operations is reversed in order to leave the document marked and unclamped. The apparatus is particularly useful for applying holographic images from tape on to documents such as cheques for authentication purposes.

Description

APPARATUS FOR APPLYING HEAT TRANSFERABLE IMAGES

This invention relates to apparatus for applying heat transferable images and particularly to applying seals using a combination of heat and pressure to documents in order to provide them with validation- or authentication.

The application of seals to documents to authenticate them extends back over centuries. Originally the seal applied consisted of a relatively thick layer of material which was applied hot or warm as a viscous pool and in which a relief impression was made using an engraved or carved seal. More recently, and more conveniently since the seal did not add materially to the thickness of the document, the hot viscous material was replaced by a layer of ink which was transferred under pressure from a relief seal and such a method is still widely used for impressing taxation stamps on documents. With the rise of image reproduction technology, however, the application of a printed design in this way is relatively easy to duplicate or forge. Accordingly, materials have been developed which make forgery considerably more difficult. These consist of transferable images which incorporate security features. Transfer is effected from a suitable carrier on which the images are formed on to the document, under the effect of heat and pressure.

In some circumstances, it is acceptable to pre- authenticate documents of value by applying such transfers during the process of manufacture of the documents. This does, however, have the major disadvantage that document^■ stock is then already authenticated and theft of stock material avoids the forger or counterfeiter having to forge or counterfeit the authenticating transfer. There is accordingly a need for apparatus which can be used simply and efficiently to authenticate documents individually and as and when needed. The apparatus must of course be secure in itself, but the physical security of such apparatus is generally easier to effect (and its theft easier to detect) than is the case for pre-authenticated stock material.

US Patent Specification 4628810 describes an apparatus which is able to effect the transfer of an image from a foil to a document by means of heat and pressure. However, this apparatus has no protective casing, rendering it unsuitable with respect to security. Furthermore, the document must be manually clamped onto the support plate of the apparatus, an operation which is both time consuming and dangerous for the operator whose hands are still brought into relatively close proximity to the heated pressure plate, even though the platen is movable to try and reduce the danger.

According to the present invention there is provided apparatus for applying a heat transferable image to a substrate which comprises a support platen co-operating with a heated die, means for locating a heat transfer material between the platen and die and for allowing the introduction of a substrate on to which the transfer image is to be transferred between the heat transfer material and the platen, a reciprocable carrier for bringing the heated die into pressure contact with the platen with the interposition of the heat transfer material and the substrate- between die and platen, and removing it therefrom, means for providing a supply of transfer material in the form of a transfer tape on a supply reel and to wind up used transfer tape on a take- up reel, and means for defining a transfer tape path between the reels, the path having a section passing between die and platen, characterised in that:

a) the reciprocable carrier is a framework and is adapted to support the take-up and supply reels;

b) the framework carries means to clamp the substrate to which a transfer is to be applied against the platen, and

c) the clamping means, tape path and heated die are so arranged that on movement of the framework towards the platen, the clamping means first engage the substrate and hold it against the platen, thereafter the transfer tape is brought to lie against the substrate, and thereafter the heated die is brought into pressure contact with the side of the transfer tape remote from the substrate, and this sequence of operations is then reversed to pull the heated die away from the transfer tape. pull the transfer tape away from the document and finally and thereafter unclamp the substrate from the platen.

Such a sequence of movement is preferably achieved by hydraulics, pneumatics or simple mechanical linkages; for example a crank drive or other eccentric drive means may be provided which, on a single rotation, causes the various parts of the apparatus to effect the sequence of operations just indicated. Alternatively, electronic timing and control means may be provided with suitable electromechanical components to effect the necessary operations. This may be done under overall microprocessor control using conventional technology, which adds to the complexity of the apparatus but provides a degree of flexibility which is not always easily achievable mechanically.

Conveniently, the clamping means consists of a pair of spring loaded bars projecting from the framework towards the platen, which move towards the platen to locate on it at positions either side of the area where the transfer will be applied, and which on contacting a substrate placed over the platen hold it resiliently against the platen with spring force while the tape is brought into contact with the substrate, and the die into contact with the tape. Preferably such clamping means are mounted on and project from the heated die.

The heated die may be of any convenient shape or size, and should match the image desired to be transferred. If this is a continuous layer on a backing tape, for example as in a conventional hot blocking foil, the area of image transferred will correspond to the area of the face of the heated die. For transferring a predetermined transferable image, it may be sufficient to use a plain flat-faced die and ensure the image is registered therewith prior to applying the heated die. Alternatively, the die may be plain and serve to apply just a small area of a continuous pattern supported on the backing tape of shape and size corresponding to the heated die. A further security feature may be incorporated by using a heated die of special shape or which, e.g., has a relief image on it. A particularly useful security transfer is one where a die having a pattern incised in its front face is used; where the incision(s) occur(s), the coating on the backing tape is not transferred, so producing an applied image having a reversed out pattern, e.g., in the form of a company logo or wording.

The platen may be adjustable in height or may be resiliently albeit firmly mounted for example by being spring mounted, to accommodate substrates of different thickness or to compensate for variations in substrate thickness or for wear in the apparatus. The surface of the platen is preferably also slightly yielding in order to compensate for any lack of alignment or variation in substrate thickness. Such modifications guarantee overall transfer and avoid the incidence of partial transfer of the transferable image or design from the tape to the substrate.

Means are provided to advance the tape following a transfer operation to bring a fresh piece of tape bearing a fresh transferable area of design into the position for being pressed by the heated die. Preferably such means are arranged to move the tape forward only as the framework is advanced towards the platen, or shortly beforehand, in order that the risk of degradation of the transferable image caused by heat emitted from the heated die is reduced.

Preferably such a tape forwarding mechanism consists of a motor which is driven to advance the tape by the desired amount, usually corresponding to the width of the die in the direction of tape transport plus a short distance e.g. a few millimetres. The distance of tape advance may be preset in the case of a tape with a continuous transferable image thereon, for example a patterned holographic image, or means may be arranged to advance the tape until a registration mark thereon reaches a suitable sensor, this method being adopted when the tape contains a series of equally spaced transferable images, each of which is required to be transferred whole on to the substrate, so that it is necessary to position each image directly facing the heated die each time the tape is advanced. When the distance of advance is preset, this may be conveniently effected by passing the tape between a pair of pinch rollers which are driven by the tape as the tape advances, one roller carrying a cam adapted to trigger a microswitch when it has carried out, e.g. one revolution. The roller circumference determines the advance.

In practice, the transfer tape used in conjunction with the present apparatus is often produced with joins along its length, the joins being covered with black tape or the like. Accordingly, the apparatus may include suitable sensors which, when they sense the black taped joins, actuate the drive motor to advance the transfer tape further than the usual desired amount in order to take the joins past the heated die. In this manner, a piece of transfer tape bearing a fresh transferable area of design is brought into the appropriate position for being pressed by the heated die.

The apparatus preferably includes means for monitoring the amount of transfer tape on the supply reel and for disenabling the apparatus if the supply of tape is nearing its end. Preferably such monitoring components include an early warning indicator to enable the user of the apparatus to see when only a small amount of stock material remains, enabling more material to be ordered or e.g. arrangements made for its release from secure storage.

Conveniently, the end of the roll of transfer tape may be tagged with a black strip of greater width than that which is often found covering any joins in the tape. When suitable sensors detect this "end-of-roll" black strip, the drive motor is at first actuated to advance the transfer tape a little further than the usual desired amount, (as when the black taped joins are detected), but since the tag is of greater width than the black tape covering the joins, then even after this first advance, the sensors continue to detect the "end-of-roll" black strip. This continued detection actuates the disenablement of the apparatus pending a new supply of transfer tape.

Additionally, the apparatus may include means to detect if the tape breaks and, if that occurs, to disenable the apparatus pending authorised repair. A suitable system is, e.g. to detect if the tape drive motor continues to run without being switched off by a cam or register mark system as described above, for e.g. greater than a preset time.

Additionally or alternatively, the apparatus may include counter means for counting the number of cycles carried out, which may be associated with cut-off means disenabling the apparatus after a given number of cycles. This is of particular value where the commercial arrangements for the use of the apparatus are based on a payment per operation, but where a full reel of transfer tape contains the potential to carry out many more operations than the user of the apparatus will wish to pay for in advance. The commercial arrangements may then be such that, for example, the user purchases the right to make 1,000 operations and as that figure is approached calls the machine supplier who will then send an engineer to reset the counting mechanism against payment for e.g. a further 1,000 impressions. If the tape supply contains enough material for several thousand impressions, resetting does not have to be accompanied by changing a used tape for a new one.

Instead of or in addition to counter means, the apparatus may include some type of gauge, meter dial indicator, or also audio or visual means to show the amount of usage, either in terms of what has been done or e.g. in terms of how much usage can still be expected before the apparatus requires attention such as resetting, or replacing the transfer tape.

The apparatus may be encased in a suitably secure housing, for example made of stout sheet metal and openable only by authorised personnel using a key which may be mechanical, electronic or a combination of both. The housing may have a slot cut into it into which the substrate on to which it is desired to apply a transfer image may be slid, and may bear appropriate indicators to indicate the status of the apparatus as well as an on/off switch and means for feeding electrical power to the apparatus in order to heat the heated die and actuate the sequence of operations required for applying an image from the transfer tape on to a substrate. Means of conventional construction may be provided to disenable the application sequence of operations until the heated die has reached a suitable operating temperature, and likewise, to prevent operations being effected unless a substrate has been inserted between the tape and platen. Photo-electric, optical or mechanical sensors may be used for that purpose. The housing may also include fixable sliding stops to limit insertion of the substrate to a desired degree, e.g. to ensure transfer of the image on to the substrate at a desired position.

The invention will be further described by way of example with reference to a specific embodiment, the major operating parts of which are diagrammatically shown in the accompanying drawings. In these drawings:

Figure 1 is a diagrammatic side view of apparatus in accordance with the present invention, and

Figure 2 is a diagrammatic end view of the apparatus seen from the left hand side as shown in Figure 1.

Referring to the drawings the apparatus is shown in highly diagrammatic form and without any outer casing.

The major frame of the apparatus consists of a pair of side plates 1, 2 connected by front and rear walls 3, 4 respectively and by a transverse crank support plate 7. Each side plate has a slot 6 in it enabling a document on to which a seal is to be applied to be inserted. The outer casing has a matching slot in it.

Within this main frame and between walls 1 and 2 is set a subframe assembly consisting of side plates 10, 11 carrying free running rollers 12, 13 14, 15 which locate the subframe between front wall 3 and rear wall 4 while allowing the subframe to be vertically reciprocated up and down.

Up and down movement is effected by a motor 20 which is fixed to side wall 1 and, via a gear box, can drive an output shaft 21. A disc 22 set on the end of output shaft 21 has eccentrically pinned into it a pin 23 having on it an upper link 24 and a lower link 25. Upper link 24 surrounds a shaft 26 which extends between side plates 10 and 11 passing through a slot 30 in each. In the position shown in Figures 1 and 2 shaft 26 is located at the top of slot 30 and acts to support the subframe formed by side plates 10 and 11 and their associated components.

Lower link 25 is pivotally connected to a shaft 32 set across the top of a heated die 34. Heating is provided by an electrical heating element 36 indicated diagrammatically in Figure 2. All wiring for this and for other components to be described later is omitted from the drawings for the sake of clarity.

Also mounted between side plates 10 and 11 are support shafts for a supply reel 40 and take-up reel 42. A strip of transfer foil tape 44, as seen in Figure 1, extends from supply reel 40 over a series of guide rolls 46, 48, 50, 52, 54, 56 and 58, then via a tape movement monitoring nip consisting of a pair of rollers 60, 62 to take-up reel 42.

Tape may be advanced by means of a tape advance motor 70 mounted on side plate 10 and which drives take-up reel 42 via suitable gearing. Associated with nip roll 62 is a cam co-operating with the actuation arm of a microswitch 64. The diameter of roll 62 is chosen such that its circumference corresponds to the desired forward tape feed each time an impression is made, or, for example, twice that desired feed length (in which case the cam co- axial with roll 62 needs two lobes rather than one to actuate microswitch 64). Once motor 70 has started operating, it continues to do so until microswitch 64 is actuated.

Also mounted between side plates 10 and 11 on the die 34 are two spring loaded presser feet 80, 82 which are set on vertically extending shafts and which are spring biased by springs around those shafts to the position shown in the Figures.

Set on a platen support plate 5 is a platen base 90 having set within it a resilient impression pad 92. Base 90 is spring mounted onto support plate 5 so that any differences in paper thickness or wear of the mechanical parts may be accommodated. Plate 5 is mounted on four threaded pins 94 which can be adjusted to raise or lower the platen slightly to optimise its position.

Tension must be maintained in practice in tape 44 between supply reel 40 and take-up reel 42. This is particularly important between idler rolls 50 and 52 since the tape in this area needs to be held sufficiently taut to enable the heated die to separate from it as discussed below.

For these reasons, supply reel 40 is gently restrained against rotation. For this purpose, as evident from Figure 1, a tension brake 98 in the form of a friction pad continuously biased against the edge of reel 40, stops reel 40 running freely. An additional friction pad 100 mounted on an arm 102 pivoted at one end on a shaft 104 is spring biased by a tension spring 106 into frictional engagement with the periphery of stock supply reel 40. When it is desired to advance the foil 44, lever 102 is pulled back by a suitable solenoid 108 connected to its left hand end as seen in Figure 1, and tape advance motor 70 is then driven. Optical sensors 114 monitor the advance of tape 44 by sensing joins in the tape and/or the end of the roll of tape. When the drive to motor 70 ceases under the control of microswitch 64, solenoid 108 is released.

Not shown in the drawings is a press button conveniently mounted in the outer casing which will initiate a sequence of operations, briefly described as follows:

Two pins 112, which are connected to two start buttons/switches or the like 113, rise and if they meet resistance from a substrate inserted into slot 6, then the buttons/switches are actuated. Clearly, if the pins rise and meet no resistance, then the buttons/switches are not actuated.

On actuating the actuation button/switch or the like. motor 70 is energised and pulls tape 44 from supply reel 40 via the tape path and nip rolls 60, 62 as shown, until the cam co-axial with roll 62 indicates that the tape has advanced sufficiently. The cam trips micro-switch 64 which turns off motor 70.

Drive motor 20 is then, or has just already been, put into operation and this rotates shaft 21 and disc 22. First of all this lowers links 24 and 25. The effect of lowering link 24 is to lower side plate 10, 11 and the components they carry. The lowering of link 25 lowers the die and the presser feet 80, 82 mounted thereon. Assuming that a document requiring authentication, for example a cheque, has been placed in slot 6 with part of it over the impression pad 92, the document is first engaged by presser feet 80, 82 which hold it firmly in place. As the assembly of side plates 10, 11 and their associated components continues to descend, the presser feet 80, 82 stay in position and prevent the document from moving.

Next the foil tape running between the guides 50 and 52 comes to lie closely adjacent the document as the assembly of side plates 10, 11 and components mounted thereon reaches its lowest position.

As disc 22 continues to rotate it lowers the die 34 into contact with the upper face of the tape 44 and, as pin 23 approaches, passes through and travels away from bottom dead centre, heated die 34 presses the tape 44 under heat and pressure against the document. At the same time, shaft 26 reaches its lowermost position of travel in the opposed slots 30 in the side plates 10, 11. As motor 20 continues to drive disc 22 the heated die 34 is first raised from the back of the tape 44, and then, as soon as pin 23 reaches the top of slots 30, the whole subframe is raised to pull the tape which is held under sufficient tension by tension brake 98 for this to take place away from the document while that document is still held against impression pad 92 by presser feet 80, 82. As the subframe and associated components continue to rise, the presser feet lift from the document enabling it to be removed with the transferable image adhering to it, and as the subframe reaches its uppermost position again, drive motor 20 is disenabled. The apparatus is then ready to apply another marking to the next presented document.

The deactuation of motor 20 may be effected by co¬ operation of part of the subframe with a micro-switch mounted on plate 1 or 2. The microswitch may also be devised to send a signal to an electronic counter which may be pre-set to indicate when the supply of foil tape is low or finished.

An alternative embodiment, which is not shown in the drawings in any detail, is a ratchet actuated system for indicating by way of a "fuel gauge" type indicator how near needing attention the apparatus is. As seen in

Figure 2, one end of shaft 26 bears an actuating member 110. As this goes up and down it is designed to move a ratchet wheel which via suitable gearing drives a rotary indicator disc part of which can be seen through a window in the outer casing. The disc bears a marking so that as the disc is (via the gearing) slowly rotated over the days, weeks or months the apparatus is put into use, the view through the window is of a gradual filling up of the area viewed, so that the user of the apparatus can see when the engineer needs to be called. A micro-switch arrangement may be associated with this rotating disc to actuate a warning when there is not much use left for the user of the apparatus to achieve and may disenable the apparatus e.g. 100 impressions or so later.

The apparatus of the present invention may be constructed and used as a stand-alone unit, i.e. independent of any other apparatus. Alternatively, it may be embodied as a module in more complex document processing apparatus, for example apparatus for automatically signing cheques or apparatus for automatically printing share certificates. In such cases, the application of the transferable image may take place before or after other marking processes have been carried out on the document.

The apparatus may also be used in conjunction with a single sheet feeder or with a tractor mechanism for feeding continuous stationery.

Claims

1. Apparatus for applying a heat transferable image to a substrate which comprises a support platen co-operating with a heated die, means for locating a heat transfer material between the platen and die and for allowing the introduction of a substrate on to which the transfer image is to be transferred between the heat transfer material and the platen, a reciprocable carrier for bringing the heated die into pressure contact with the platen with the interposition of the heat transfer material and the substrate between die and platen, and removing it therefrom, means for providing a supply of transfer material in the form of a transfer tape on a supply reel and to wind up used transfer tape on a take- up reel, and means for defining a transfer tape path between the reels, the path having a section passing between die and platen, characterised in that:

c) the clamping means, tape path and heated die are so arranged that on movement of the framework towards the platen, the clamping means first engage the substrate and hold it against the platen, thereafter the transfer tape is brought to lie against the substrate, and thereafter the heated die is brought into pressure contact with the side of the transfer tape remote from the substrate, and this sequence of operations is then reversed to pull the heated die away from the transfer tape, pull the transfer tape away from the document and finally and thereafter unclamp the substrate from the platen.

2. Apparatus according to claim 1 and including a crank drive or other eccentric drive means which, on a single rotation, causes the various parts of the apparatus to effect the sequence of operations set forth in claim 1.

3. Apparatus according to claim 1 or 2 wherein the clamping means consists of a pair of spring loaded bars projecting from the framework towards the platen which move towards the platen to locate on it at positions either side of the area where the transfer will be applied, and which on contacting a substrate placed over the platen hold it resiliently against the platen with spring force while the tape is brought into contact with the substrate, and the die into contact with the tape.

4. Apparatus according to any one of claims 1 to 3 and including means to advance the tape following a transfer operation to bring a fresh piece of tape bearing a fresh transferable area of design into the position for being pressed by the heated die.

5. Apparatus according to Claim 4, wherein such means are arranged to move the tape forward only as the framework is advanced towards the platen, or shortly beforehand, in order that the risk of degradation of the transferable image caused by heat emitted from the heated die is reduced.

6. Apparatus according to any one of claims 1 to 5 and including a tape forwarding mechanism consisting of a motor which is driven to advance the tape and a pair of pinch rollers cooperating with means monitoring their rotation to stop tape movement after a desired amount.

7. Apparatus according to any one of claims 1 to 6 and including counter means for counting the number of cycles carried out and associated with cut-off means disenabling the apparatus after a given number of cycles.

8. Apparatus according to any of Claims 1 to 7 and including a sensing means which is capable of detecting when a substrate is located between the heat transfer material and the platen.

9. Apparatus according to Claim 8 wherein the sensing means is optical, electronic or mechanical.

10. Apparatus according to any of claims 1 to 7 and including a secure housing openable only by authorised personnel using a mechanical, electronic or a combination key.