WO2002094581A1

WO2002094581A1 - Image transfer apparatus and method

Info

Publication number: WO2002094581A1
Application number: PCT/GB2002/002394
Authority: WO
Inventors: Robert Adrian Shaw; Neil Anderson; Peter Richard Herring; Dr. Jeffery Michael Howell
Original assignee: Micyte Limited
Priority date: 2001-05-22
Filing date: 2002-05-22
Publication date: 2002-11-28

Abstract

Image transfer apparatus (10) transfers an image from a printed transfer sheet (200) into a clear lacquer coating which has been previously applied to a component (100). The image transfer is effected by the application of heat and pressure to the transfer sheet (200) and component (100), by means of a resilient, heated pad (46) into which the transfer sheet and component are urged. The pad (46) is heated by means of an aluminium heater block (41) and the transfer sheet (200) and component (100) are urged into engagement with the pad (46) by a lifting mechanism (20). The component handling section (60) comprises a drawer (61) on which is mounted a transfer sheet support means (63). The component support means (80,86) is slidably mounted within the transfer sheet support means. When the drawer (61) is closed, the lifting mechanism (20) raises the component (100) and transfer sheet (200) to a pre-conditioning position close to the heated pad, so that the transfer sheet is softened, and then further raises the component (100) relative to the transfer sheet, pushing the component into engagement with the heated pad, through the transfer sheet (200).

Description

Image Transfer Apparatus and Method

The present invention relates to an image transfer apparatus and method, and in particular to an apparatus which is suitable for thermally applying an image to the surface of a product.

In recent years, there has been an increased demand for a greater variety of different colours, images or finishes on a variety of consumer products, with the desire to give the product an individual or personalised appearance. Such products may include mobile phone casings, pagers, computer mice, or any product where surface decoration may be desirable.

Several industrial image transfer processes are known. One such process is commonly referred to as the "dip print" process, in which the image is applied to a water-soluble film by means of an ink jet printer. The film is floated on the surface of water, and the product is then dipped into the water, through the ink and dissolving film layers. The pressure of the water on the product ensures that the ink is applied evenly to it. A refinement of this process is disclosed in International Patent Application No. WO00/20128 (4Cyte Limited). Another industrial process employs heat to transfer an image from a pre-printed film to the product surface. This process is used to transfer images onto the surfaces of mugs, for example.

Other processes include spray-painting, ink jet printing or tampo- printing directly onto the object. Until now, known image transfer processes for product decoration have required relatively large, industrial-grade apparatus and machinery. Because of this, products have tended to be processed in relatively large batches with a small number of "off the shelf image designs available. Individual images to the customer's specification can of course be produced by these processes, but often the customer is required to purchase a minimum, usually large, number of decorated products to make the process viable. Known processes are therefore relatively inflexible and do not lend themselves readily to small batch production, or more importantly to one-off designs. They also require substantial capital outlay by the company providing the image transfer service.

From a first aspect, the present invention provides an image transfer system in which an image is transferred from a transfer sheet onto a component by pressing the transfer sheet onto the component using a heated resilient pad.

By providing an image transfer system that uses a resilient pad to transfer an image from a transfer sheet onto a component, the invention provides a very versatile and flexible image transfer system, particularly in terms of the type of image that can be transferred and the shape of component onto which an image can be applied.

The present invention also provides apparatus capable of applying an image in this manner. In accordance with a further aspect therefore, the present invention provides an image transfer apparatus for thermally transferring an image from a transfer sheet to a component, comprising a resilient pad, means for heating the resilient pad to a predetermined temperature, and means for supporting the component in use, wherein the component support means is movable in use from a first component position in which the component is spaced from the resilient pad, to an image transfer position in which at least part of the component is urged into engagement with the heated resilient pad through the transfer sheet such that the image on the transfer sheet is transferred to the component.

Preferably, a housing is provided in which is mounted the resilient pad and the heating means. To provide access to the component and transfer sheet support means, a drawer is preferably provided on which these means are mounted. During operation of the apparatus and image transfer, the drawer is closed and the apparatus functions as described, with the component and transfer sheet support means within the housing. When it is necessary for the transfer sheet and/or component to be loaded or unloaded, the drawer can be opened to enable access to the support means.

The means for heating the resilient pad preferably comprises a heater in heat communication with the pad. Preferably, the heating means comprises an aluminium heater block which is electrically heated by means of cartridge heaters therein. The heating means should be sufficient to heat the resilient pad to a temperature range of between 100°C and 240°C in use (at least in its interior region).

The resilient pad is preferably inherently resilient, but may instead or as well be resiliently mounted. Essentially, by virtue of its resiliency or resilient mounting, the pad should substantially conform to the profile of the component surface which engages therewith in use. The pad may, however, be shaped at least in part to accommodate the component.

The pad may be made of any material suitable for performing the described function. Preferably, it should be resilient and flexible whilst being able to conduct heat, and therefore a compromise may be necessary to achieve thermal conductivity and conformance to shaped parts. Preferably, the pad is formed from silicone which contains aluminium. More preferably, the pad is formed from a silicone foam according to the teachings of UK Patent Application No. 0100330.0 filed on 6 January 2001 in the name of Imperial Chemical Industries pic, a copy of which is being submitted with the present application.

The pad preferably comprises a generally rectangular block and is preferably sized to suit a particular component or type of component. The pad may have any suitable thickness to perform its function and to exhibit the desired properties. Preferably, the pad is between 4mm and 20mm in thickness. A pad suitable for transferring images onto mobile phones, for example, may have a length of around 100-150mm, a width of around 60- 100mm, and a thickness of around 7-15mm.

Preferably, the surface of the pad which contacts the transfer sheet in use is textured to reduce adhesion between the pad and the transfer sheet and/or component. The texturing pattern may take any suitable form, but is preferably random. The depth of the texturing may be between 0.01 -5mm, but is preferably about 0.2mm. The spacing between the indents, grooves or depressions making up the texturing pattern may be between 0.01- 10mm, but is preferably about 0.3mm. The pad may be formed with an integrated metal plate which may for example be resiliently mounted to the heater block say by means of spring clips. For example, the pad may be moulded onto a perforated aluminium plate. In this way, the pad is supported by the plate and heat is transferred from the heater block to the plate and then to the resilient pad. In a preferred form, however, the resilient pad comprises a discretely formed resilient element. It is preferred that the pad comprises a discretely formed element since it has been found that a separately formed pad can have a greater working life-span. In particular, a discretely formed pad may be less susceptible to wear which may be caused if the pad is constructed from materials having different thermal characteristics. Savings in manufacturing costs may also be made due to the simple construction of the pad. To achieve efficient transfer of heat to the pad, preferably means are provided to hold or retain the pad in close proximity to the heating element. The pad may therefore be provided with any suitable support means to locate the pad in position adjacent to the heating element, and if desired, to press the pad against the heating element. The pad support means may comprise, for example, a number of brackets attached to the heating element, or to other structures within the apparatus, and which extend beneath the pad to provide support.

Preferably the support structure for the pad comprises a surround which generally encloses the pad but allows a component to be pushed into the lower face of the pad during the image transfer process. In a preferred form, the pad support comprises a metal surround which extends along the sides of the pad and includes a number of flanges that extend a short distance beneath the lower face of the pad so that the pad is held in place. Preferably, supporting flanges are provided along two opposed edges of the pad.

In use, when the pad is under load, i.e. when a component is pushed into the pad, the pad deforms. Specifically, the pad is compressed in the area proximate to the component and becomes thinner in this area. This deformation enables the pad to conform to the shape of a particular component which can improve the image transfer process.

The flexible material of the pad however is pushed sideways, away from the component and towards the surrounding pad support structure. Preferably, therefore, the pad and/or the pad support is arranged to accommodate the movement of the pad as it deforms and thus provide predictable and controlled deformation of the pad.

Preferably, the pad and the pad support are arranged to provide space into which the material of the pad can expand as a component is pressed into the pad. The pad may, for example, be formed with a volume less than that defined by the pad support. In a preferred form, however, the pad includes one or more cutaway portions around the edges of the pad. In use, with the pad received within its support, the pad does not fill the volume defined by the pad support but instead the cutaway portions provide space into which the pad can expand. The use of cutaway portions, say as opposed to simply making the pad smaller than the volume defined by the pad support, enables the pad to be more accurately located in position whilst still providing sufficient space for expansion of the pad when it is compressed.

In a particularly preferred form, the pad comprises a generally block- shaped element which has a planar upper surface and a planar lower surface. The side walls of the pad extend from the upper surface but are then stepped inwardly to provide a cutaway portion in the form of an overhang at the edge of the pad.

From a further aspect therefore, the present invention provides a resilient heating pad for use in an image transfer process, comprising a generally block-shaped element which has a generally planar upper surface, a generally planar lower surface and side walls, wherein at least a portion of the edge of the pad is formed with side walls that extend from the upper surface but are then stepped inwardly to provide a cutaway portion in the form of an overhang.

Preferably, the overhang extends around the perimeter of the pad, although the overhang may be provided along any desired regions of the edge of the pad.

In the above pad arrangement, preferably means are provided to improve contact between the pad and the heating element, particularly prior to the pad being engaged and deformed by a component. The edge regions of the pad that are formed with overhangs are therefore preferably provided with one or more supporting elements. The supporting elements occupy some of the volume defined by the overhang but sufficient space is maintained into which pad material can expand when the pad is compressed. The supporting elements do however act to maintain the upper face of the pad against the heating element, or at least in close proximity to the heating element, particularly in the pre-heating stage of the image transfer process when the pad is not compressed. The support structures may also serve to ensure that the pad is heated evenly.

The supporting structures of the pad may take any suitable form but preferably comprise a number of resilient formations that project into the overhang defined by the side walls of the pad. The supporting structures may take any suitable form, such as ribs, spikes, domes and so on, provided that there is space between the supporting structures into which pad material can expand. Preferably, the supporting structures comprise a number of spaced generally cylindrical elements that extend downwardly from the underside of the overhang and terminate generally at the level of the lower face of the pad. The supporting structures may comprise separately formed elements which are then attached to the pad but preferably the supporting structures are integrally moulded from the resilient material of the pad.

In a particularly preferred arrangement in which the pad is held against the heating element by flanges that extend beneath edges of the pad, the support structures extend along these edges such that the pad is substantially supported by the supporting structures.

In preferred embodiments, means are provided for supporting the transfer sheet in use between the pad and the component. The transfer sheet support means is preferably movable from a first transfer sheet position in which the transfer sheet is spaced from the pad to a second transfer sheet position in which the transfer sheet is proximate to the pad. In the second transfer sheet position, the transfer sheet would be close to, but would not normally contact, the resilient pad. In this position, the transfer sheet is preferably between 1mm and 3mm from the heated pad, and more preferably within 2mm. The transfer sheet only contacts the pad in this position when the component is in the image transfer position, and the component stretches or otherwise distorts the transfer sheet such that both transfer sheet and component are at least in part urged into contact or engagement with the resilient pad.

In preferred embodiments, the component support means is movable to a second component position intermediate the first component and image transfer positions. When in the second component position, the transfer sheet support means is in the second transfer sheet position, proximate to the resilient pad. Both the transfer sheet and the component are therefore relatively closer to the resilient pad than in their respective first positions, which is suitable for pre-conditioning the component and/or transfer sheet. This pre-conditioning position may be desirable in order that the transfer sheet is softened prior to transfer of the image to the component, for example. This softening allows the transfer sheet more easily to conform to the exterior shape of the component in contact therewith, and to exclude as much air as possible from between the two surfaces. The spacings referred to above between the transfer sheet and resilient pad optimise the preconditioning of the transfer sheet. Preferably, means are provided in the apparatus to move the component support means between its three positions described above, and means are also preferably provided to move the transfer sheet support means between the two transfer sheet positions. These can be any suitable mechanical or electrical means for performing the stated function, and the same means could in fact perform both functions. Preferably, the movement function is provided by a lifting mechanism, such as a scissor mechanism, driven by an electric motor. Preferably, the lifting mechanism is able to provide a pressure of up to about 5.5 kg/cm² between the component and the resilient pad in use. The use of a scissor lift has been found advantageously to provide a corrective moment to prevent the uneven forces across the component area skewing the component as it is pressed into the pad.

For obvious reasons, it is preferred that in use, the component is only moved to the second (pre-conditioning) position at the same time as or after the transfer sheet is moved to its respective second (pre-conditioning) position. The transfer sheet then remains in this position following pre- conditioning, whilst the component is moved to the image transfer position in contact with the resilient pad to effect the image transfer.

The component support means and the transfer sheet support means are preferably arranged such that they can be moved together from their respective first positions to their respective second (pre-conditioning) positions, and such that the component support means is then able to move relative to the transfer sheet support means to the image transfer position. In accordance with a particularly preferred embodiment, the two support means are able to move relative to each other, say by a slidable connection, and are urged towards a particular relationship by some form of resilient means, such as spring means or the like interposed between the component support and the transfer sheet support. Thus, when both support means are in their first positions, the arrangement is preferably such that a force acting on the component support means to move it towards its second (preconditioning) position will also cause a generally corresponding movement of the transfer sheet support means towards its second (pre-conditioning) position. Both support means can therefore be lifted together due to the resilience of the spring means maintaining the relative positions of the two support means. The two support means therefore generally move together until the transfer sheet support means reaches its second position in which it can be pre-conditioned, say by pre-heating prior to image transfer. In this position, the transfer sheet support means is preferably stopped, say by the provision of one or more suitable stops, so that it is unable to move any further towards the heating means.

Once movement of the transfer support means has stopped, the force preferably continues to act on the component support means. The force therefore compresses the spring means so that the component support means begins to move relative to the transfer sheet support means towards its second position and the component moves towards the transfer sheet. Once the component support means is in its second position, the component is located below but in close proximity to the transfer sheet. In this position, both the transfer sheet and the component are positioned for pre-conditioning by pre-heating. Preferably, both support means are maintained in their second (pre-conditioning) positions for a predetermined length of time until the transfer sheet and the component are ready for the process of image transfer.

When pre-conditioning is complete, further force is applied to the component support means. The transfer sheet support means maintains its position due to the presence of one or more stops, however, the component support means is able to move by further compression of the spring means. Thus, the component moves towards and through the transfer sheet and into engagement with the heated resilient pad. In this step of the process, the portion of the transfer sheet in contact with the component is stretched or otherwise deformed by the component as the component moves to the image transfer position while the outer periphery at least of the transfer sheet remains in the second (pre-conditioning) position.

Any suitable mechanism to provide the described movement relationship is envisaged. As will be seen from the description of a preferred embodiment below, one preferable mechanism includes a generally U- shaped transfer sheet support means, the transfer sheet being supported in use across the tops of the "U". The transfer sheet support means defines a component cavity within the "U". Clearly, the transfer sheet support means will have depth as well as width, so that a transfer sheet can conveniently be supported at or near each corner. The transfer sheet support means may not be solid, but instead could resemble an up-turned table, with sufficient support members extending up from the base to support the transfer sheet in use. In a preferred arrangement, the transfer sheet support means comprises a box-like container of a generally U-shaped cross-section. The container preferably comprises a base from which extend side walls and in which the component support means can be located. The upper edges of the side walls, that is the edges furthest from the base of the container, are formed with an inwardly projecting lip which extends around the upper edges of the side walls. The lip defines an aperture through which the component can project and also provides a surface on which the transfer sheet can be placed so that it extends over the aperture.

The component support means is preferably l-shaped in cross- section, with the central section of the "I" being slidably mounted in the bottom surface of the U-shaped transfer sheet support means. The component may be mounted on the upper flange of the "I", inside the component cavity. Spring means can therefore be positioned between the underside of the "U" and the lower flange of the "I" such that the two support means are urged towards a position in which the upper flange is at its lowermost position inside the "U". A force acting on the lower "I" flange in the upwards direction will therefore cause both support means to move together, until the transfer sheet support means reaches its second (preconditioning) position and abuts against one or more stops. Continued force on the component support means will cause this support means to move relative to the transfer sheet support means, with the upper "I" flange moving upwards inside the "U", such that the component support means can reach its second (pre-conditioning) position and is capable of moving beyond this position to the image transfer position. It can therefore be seen that, with the component and transfer sheet appropriately positioned in use, the pre-conditioning and image transfer functions can be realised as described above.

The means for supporting the component preferably includes a nest which, at least in preferred embodiments serves, to locate and act as a mechanical support for the component to prevent distortion during the image transfer process. Thus, the nest is preferably specifically designed and manufactured for a particular component, and preferably also has specific thermal characteristics relevant to that component. Preferably, the nest is relatively rigid and non-deformable, at least in comparison to the pad.

The materials of construction of the nest may be chosen in accordance with the teachings of UK Patent Application No. 0100330.0, referred to above. Preferably, the nest is made from unfoamed silicone resin, at least in the region which contacts the component in use. Furthermore, to ensure the nest does not progressively accumulate heat between successive uses, the nest material in contact with the component is preferably kept as thin as possible. This may be achieved by forming the nest material over an internal support or former which preferably follows the contours of the component. Preferably, the nest material is of substantially uniform thickness. Preferably, the nest material is less than 8mm in thickness, and more preferably between 2 and 4mm in thickness.

Furthermore, to allow a thinner layer of the nest material, its thermal conductivity may be reduced by making it from a foamed resin, or incorporating particles which have thermal insulating properties. Those skilled in the art will be able to select appropriate materials and dimensions to optimise the performance.

Preferably the nest is temperature controlled. Means may therefore be provided in the apparatus to control the nest support temperature. Preferably the nest support has a higher thermal conductivity than the nest surface material, and is more preferably made from a metal, or metal-filled resin. The nest or nest support may be cooled for example by thermal conduction to a heat sink.

In a particularly preferred embodiment, the nest is provided with means identifying one or more component characteristic or one or more process parameter. The various process parameters are discussed in more detail below, and will be apparent to the skilled person on reading the remainder of the specification. The identifying means may comprise a barcode, or one more metal contacts, magnetic strips, notches, projections, pins or holes, for example. The apparatus may therefore be provided with means for reading or interpreting the identifying means such that the desired process parameters can be selected. This may comprise a reader appropriate for the examples of identifying means given above. One particularly preferred embodiment employs micro switches to sense notches or projections on the nest. Information about the component or the process parameters may be presented in the identifying means in code form, readable by the reader. A single code may serve to designate one, some or all of the various process parameters. Alternatively or in addition, once determined, the code can then serve as the coordinates in a look-up table to establish the process parameters.

As an alternative, the apparatus may be provided with means for recognising the component itself from one or more features thereof. In this case, or in the case of an appropriate identifying means on the nest, the apparatus may be provided with some form of optical or visual recognition system which is able to identify one or more features of the component or nest. In preferred embodiments, means for sensing the position of the component, nest, component support means, transfer sheet support means or lifting mechanism are provided. This may comprise one or more micro- switches or optical switches. Means may also be provided for sensing the position of the drawer, and whether it is open or closed for example. The transfer sheet support means preferably includes means for retaining the transfer sheet in use. This could comprise a spring-loaded clamp, for example. Means may also be provided on the transfer sheet support means and/or on the transfer sheet to ensure correct location and orientation of the sheet, such as appropriate use of indicators, pins, arrows or the like on one or both components.

Means are preferably provided to prevent the transfer sheet from sticking to the heated pad after image transfer and retraction of the transfer sheet support means. One preferred arrangement is to provide a stripper plate which clamps the used transfer sheet to the support means as the support means moves back to the first position. This ensures that the transfer sheet is removed cleanly from the heated pad and is not left adhered thereto. The stripper plate may be operated by means of one or more solenoids.

In a preferred arrangement, the means that retain the transfer sheet on its support also serve to prevent the transfer sheet from sticking to the heated pad after image transfer. For example, as described above, the upper edges of the side walls of the transfer sheet support means may be formed with an inwardly extending lip on which the transfer sheet can be placed. With this arrangement, a stripper plate can be placed over the transfer sheet such that the transfer sheet is sandwiched between the stripper plate and the transfer support means. In this arrangement, the stripper plate both retains the transfer sheet in use and also prevents the transfer sheet from sticking to the heated pad after image transfer. Preferably, the stripper plate is formed with an aperture which generally corresponds in size and shape to the aperture defined by the lip and through which the component can extend into contact with the heated resilient pad. The stripper plate may be placed over the transfer sheet by any suitable means. In a preferred form, the stripper plate is hingedly connected to the transfer sheet support means. The stripper plate can therefore be hinged to an open position so that a transfer sheet can be loaded onto the transfer sheet support means and then hinged to a closed position in which the periphery of the transfer sheet is sandwiched between an upper surface of the lip of the transfer support means and a lower surface of the stripper plate.

As described above, the movement of the transfer sheet support means and the component support means can be largely controlled by the application of force to the component support means. Preferably, however, means are provided to further control the movement of the two support means, particularly to selectively lock the relative positions of the two support means during processing of a component.

Any suitable means may be provided to lock and/or control the relative movement of the transfer sheet support means and the component support means. Preferably, some form of catch is provided which selectively locks relative movement of the two support means. A catch may therefore be provided which extends between the transfer sheet support means and the component support means to selectively lock these two components relative to each other. Most preferably, a catch is provided that can selectively prevent relative movement of the two support means when the support means are spaced at a first distance and also when they are spaced at a second distance as will be described in more detail below.

Most preferably, the catch selectively connects the stripper plate to the component support means in order to prevent relative movement of the transfer sheet support means and the component support means. In a preferred arrangement therefore, a catch is attached to the stripper plate and the component support means is provided with means, such as one or more lugs or projections, which can be selectively engaged by the catch to connect the stripper plate and the component support means. Preferably, the catch is located adjacent to a side wall of the transfer sheet support means and the lug or lugs of the component support means extend through one or more apertures formed in the side wall. Many other suitable arrangements of selectively connecting the stripper plate and the component support means will also be apparent.

The function of the catch is best understood by describing the apparatus in use. Prior to loading the apparatus with a transfer sheet, both the transfer sheet support means and the component support means are preferably in their first positions. A stripper plate is hingedly attached to the component support means so that the stripper plate can be lifted and a transfer sheet placed on a lip of the transfer sheet support means as described above. The transfer sheet is therefore sandwiched between the stripper plate and the lip.

With the transfer sheet in position and the stripper plate closed, a catch attached to the stripper plate is moved into engagement with means formed on the component support means. This effectively locks the stripper plate in place. The means on the component support means that is engaged by the catch preferably comprises a lug that extends from the component support means through an aperture in a side wall of the transfer sheet support means so that the lug can be engaged but the catch.

The lug preferably comprises a generally cylindrical member formed on the component support means and which extends through an elongate aperture formed in a side wall of the transfer sheet support means. The aperture is elongate so that the lug can move within the aperture during relative movement of the two support means. The aperture is preferably of a width slightly greater than the width of the lug such so that the aperture may serve to guide movement of the lug and thus guide movement of the component support means relative to the transfer sheet support means. For this reason, it is preferred that a number of such lugs are provided, say three spaced lugs extending through opposing side walls of the transfer sheet support means, to further guide the two support means during relative movement. If a number of such lugs is provided, it is preferred that only a single catch is provided that engages a single lug, however, a number of catches may be provided that engage a number of lugs.

With the transfer sheet loaded and the catch engaged, the drawer of the press is shut and the press is then started. Initially, the component support means is in its first position and is spaced at a distance from the heating means. In this position, each lug is located in and extends through a bottom end of its respective aperture. The lifting mechanism, preferably a scissor lifting mechanism, is then activated to engage the lower flange of the component support means such that the two support means are lifted and move together until the transfer sheet support means reaches its second

(pre-conditioning) position and abuts against a stop. Continued force on the component support means then causes the component support means to move relative to the transfer sheet support until it reaches its second (preconditioning) position in which the component is close to but beneath the transfer sheet. The two supports are then maintained in this position for sufficient time to allow the component and the transfer sheet to be pre- heated. When pre-heating is complete, the lifting mechanism applies further force to the component support means to further compress the spring means. This causes the component support means to move to its image transfer position and causes the component to move through the transfer sheet and into engagement with the heated resilient pad. In this position, with the component engaged with the resilient pad, the catch moves so that the lug is engaged by a second portion of the catch so that the component support means and the transfer sheet support means are held relative to each other but at a distance closer than they were previously held by the catch. Once the step of image transfer has been completed the lifting mechanism lowers. If a catch was not provided the lowering of the lifting mechanism would cause the component support means to move away from the heating element and towards its first position but the transfer sheet support would remain in its second pre-conditioning position due to expansion of the spring means. Thus, relative movement of the component and the transfer sheet would occur as the spring means expanded which would separate the transfer sheet from the component.

By providing a catch, however, the component support means and the transfer support means can be locked together with the transfer sheet stretched over the component. The catch therefore holds the spring means in compression, and prevents relative movement of the two supports. The lowering the of lifting mechanism thus causes the two supports to move together away from the heating element and towards a position in which the transfer sheet and the component can cool. The provision of a catch therefore allows the transfer sheet and the component to be kept in contact as they are lowered and also during the cooling process and this can enable improved quality of image transfer.

The lifting mechanism lowers until the component support means returns to its first position, i.e. its position prior to loading of a transfer sheet. The first position of the component support means is also therefore the cooling position of the component support means. The transfer sheet support means is however located below its first position since the spring means are held in compression by the catch.

Whilst in the cooling position, preferably cooling means are provided to actively cool the component and/or transfer sheet after image transfer. The cooling means may also function to cool the component support means or nest, and the transfer sheet support means. Suitable cooling means may comprise an electric fan.

After a sufficient period of cooling, the catch is released and the spring means expand to move the transfer sheet support means relative to the component carrying means and back to its original first position. The movement is caused by expansion of the spring means and also serves to separate the component from the transfer sheet which retained by the stripper plate. The stripper plate can then be opened and both the transfer sheet and the component can be removed from the apparatus. The apparatus is then ready for the process to be repeated. As mentioned above, previously known image transfer processes have required relatively large, industrial-grade apparatus. By virtue of the various features of the present invention described above, it has been possible to make the apparatus much smaller than known machines. Preferably, the apparatus is designed to take only a single component, although it may of course be possible to load more than one component if the dimensions of the component cavity allow and a suitable nest is provided. The overall dimensions of the apparatus are designed to be similar in size to a desktop tower PC. By providing relatively straightforward lifting mechanisms and support mechanisms, together with the arrangement of providing the support mechanisms on a slidable drawer to allow access to the component and transfer sheet in use, a relatively compact machine can be produced.

The image transfer apparatus in accordance with the invention is essentially a single-component single-operation image transfer press. The drawer is opened, the component and transfer sheet loaded into position, and the drawer is closed to commence the automated image transfer process. On completion of this, the drawer can be opened and the used transfer sheet and finished component can be removed. Thus, the apparatus is very simple to operate, and is very suitable for producing one- off decorated components. Individual designs or images can be designed or specified, which can then be printed on a suitable transfer sheet by any suitable process using suitable inks. That image can then be applied to the component as described above, and a unique component can result.

The apparatus is also extremely flexible. As mentioned above, one- off images can be applied to a transfer sheet and subsequently applied to the component. By having a component nest which is specifically designed for a particular component, different components can be placed in the apparatus simply by employing an appropriate nest.

The apparatus is particularly suited for decorating consumer products such as mobile phone casings or pager casings, for example. A customer may wish to have his or her particular design (this could be a graphic or a photograph, for example) applied to the exterior of his or her own mobile phone. The customer can create or select the desired image, and the transfer film is then printed. The machine operator simply then selects the appropriate nest for the customer's phone casing, and commences the image transfer process as described. Within a relatively short space of time, the customer has an individualised phone.

The various functions of the apparatus as described above may be controlled by an internal controller having a microprocessor and a memory. There may also be provided an operator interface on the exterior of the machine, such as a display and keypad. Alternatively, the apparatus may be controlled by software running on a conventional computer which is connected to the apparatus. The computer may also be used to acquire an image from a source, to manipulate the chosen image to fit a particular component, to add any additional text or graphics, to display a representation of the completed image on the component, and finally to print the completed image onto transfer sheet in reverse format suitable for a transfer, such that the transfer sheet is printed and ready for the transfer process.

In accordance with another aspect, therefore, the present invention provides a system comprising an image transfer apparatus having one or more features described herein and a computer having software adapted to control the image transfer apparatus. The system may additionally comprise a printer, also controlled by software in said computer, which is adapted to print on a transfer sheet suitable for use in the image transfer apparatus. The system may further comprise scanning means for scanning a particular image, this image being converted to bitmap form by software in said computer. The computer may also be adapted to obtain images from other sources, such as the Internet. In accordance with a further aspect, the invention provides a method of transferring an image from a transfer sheet to a component in an apparatus comprising a resilient pad, means for heating the resilient pad to a predetermined temperature, means for supporting the component in use, and means for supporting the transfer sheet in use between the component and resilient pad, the method comprising the steps of placing the component on the component support means, placing the transfer sheet on the transfer sheet support means, heating the resilient pad to the predetermined temperature, and moving the component from a first component position in which the component is spaced from the resilient pad, to an image transfer position in which at least part of the component is urged into engagement with the resilient pad through the transfer sheet, such that, when the component and transfer sheet are in engagement with the heated resilient pad for a predetermined time, the image on the transfer sheet is transferred to the component.

The method may additionally comprise the step of moving the transfer sheet from a first transfer sheet position in which the sheet is spaced from the pad to a second transfer sheet position in which the sheet is proximate to the pad. This would be carried out prior to or at the same time as moving the component. In the second transfer sheet position, the transfer sheet is preferably between 1mm and 3mm from the heated pad, and more preferably within 2mm. The transfer sheet only contacts the pad in this position when the component is in the image transfer position, and the component stretches or otherwise distorts the transfer sheet such that both transfer sheet and component are at least in part urged into contact or engagement with the resilient pad.

The method may additionally comprise the step of pre-conditioning the transfer sheet and/or component prior to image transfer. The method may therefore comprise the step of moving the component to a second component position intermediate the first component and image transfer positions, at the same time as or after the transfer sheet is moved to the second transfer sheet position, proximate to the resilient pad. As mentioned above, both the transfer sheet and the component are relatively closer to the resilient pad than in their respective first positions, which is suitable for pre- conditioning the component and/or transfer sheet.

Following the image transfer step, the method may additionally comprise the steps of withdrawing the component to the second component position, and subsequently withdrawing the component and transfer sheet to their respective first positions. The transfer sheet may be withdrawn at the same time as or after the component. The further step of cooling the component may be employed. The transfer sheet may be A6-sized, and the image to be transferred may be up to about 105mm x 85mm. The transfer sheet may be formed from any suitable material, such as paper, film or a laminate, but it should obviously be able to withstand the temperatures that will be encountered when in contact with the heated pad. The image on the transfer sheet may be produced by a variety of different printing techniques, including electrophotography, mass transfer printing, ink jet printing, melt or wax transfer printing, and dye diffusion thermal transfer printing. Appropriate carrier sheet material will need to be used in each case. The image which can be transferred by the apparatus of the present invention may be as straightforward as a single colour or shading, or possibly a surface texture or coating. Alternatively, the image may include more than one colour, and my be a full-colour photographic quality image. Accordingly therefore, the term "image" should be construed broadly. In order to provide a suitable surface to receive the ink or other material forming the image, the component is preferably pre-treated prior to the application of the image, for example by applying a coating of lacquer to the component surface. Any coating or pre-treatment should be compatible with the chemicals or material forming the image, and those skilled in the art will be able to make an appropriate selection in each case.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Fig. 1 shows a cross-sectional side view of an image transfer apparatus in accordance with the invention; Fig. 2 shows a cross-sectional view of the same apparatus, as seen from the drawer end; and

Fig. 3 shows a more detailed cross-sectional view of the component handling section of the apparatus; and

Fig. 4 shows a block diagram of the main components of the image transfer apparatus.

Figs. 5 through 9 show a further embodiment of the invention at different stages in its operating cycle; Fig. 10 shows a detail of the embodiment of Figs. 5 to 9; and Figs. 11 through 14 show a preferred form of resilient pad for use with the invention.

A detailed description of the operation of the apparatus is given below. In summary, image transfer apparatus 10 transfers an image from a specially-printed film sheet, or transfer sheet, 200 into a clear lacquer coating which has been previously applied to a component 100. The transfer is effected by the application of heat and pressure to the transfer sheet 200 and component 100, by means of a resilient, heated pad into which the transfer sheet and component are urged.

Image transfer apparatus 10 comprises three main functional groups: lifting mechanism 20, heater section 40 and component handling section 60. The apparatus 10 is a desktop device, similar in size to a desktop tower PC but slightly wider. The apparatus operates from a single 100-240v ac power supply, at approximately 1.6kW. The apparatus can therefore be conveniently used in a retail environment.

Lifting mechanism 20 comprises a scissor mechanism 21 which is driven by an electric motor to raise component 100 and transfer sheet 200 to the image transfer positions as will be described below. Scissor mechanism 21 comprises a pair of scissors 22 which act on lifting plate 23, and the lifting mechanism can develop up to 500kg of force at its highest position (or about 5.5kg/cm² over the 90cm² image area). The scissor lift can advantageously provide a corrective moment to prevent the uneven forces across the component area skewing the component 100 as it is pressed into the pad. Position-sensing switches (not shown) can be employed to detect the position of lifting plate 23 or other part of the mechanism.

Heater section 40 comprises an aluminium heater block 41 which is electrically heated by means of cartridge heaters 42 (Fig. 2). The block is insulated from the casing of the apparatus by means of insulation pad 43. Beneath heater block 41 is a compliant pressure pad 46, which is made from silicone foam loaded with aluminium and softening agent, in the following proportions (% of final mass):

45.5% Silistic "S" base, available from Dow Corning 4.5% catalyst (Silistic "S" curing agent, available from Dow Corning)

22.5% silicone fluid (Dow Corning 200/50cs) 27.5% aluminium powder (e.g. Fisher Chemicals Aluminium A/1605/53)

The pad 46 is formed by first mixing the compound, leaving it for approximately 90 minutes, re-mixing and then pouring into a mould. The mixture is then left for a further 30 minutes and then cured at approximately 65°C for a period of two hours. This process facilitates even distribution of the aluminium powder without causing the softening agent and mechanically-trapped air to separate.

Pad 46 is also formed with an integrated perforated aluminium plate 47, which is resiliently mounted to the heater block by means of spring clips 48. In this way, heat is transferred from the aluminium heater block 41 to the pressure pad 46. The pad itself is resilient, and is mounted resiliently, such that when the component is urged against it by the lifting mechanism 20, the pad will substantially conform to the profile of the component surface. The surface of the pad may also be textured to reduce adhesion between the pad and the transfer sheet 200 and/or component 100. A compromise may be necessary, however, in order that heat transfer is not unduly restricted due to the presence of air or gasses trapped in the texture pattern. The texturing pattern may take any suitable form, but is preferably random. The depth of the texturing may be between 0.01 -5mm, but is preferably about 0.2mm. The spacing between the indents, grooves or depressions making up the texturing pattern may be between 0.01-10mm, but is preferably about 0.3mm.

Heater block 41 is also provided with an over-temperature cut-out device and a temperature probe (not shown). As mentioned above, the temperature range of the pad in use is between 100°C and 240°C.

With reference to Fig. 3, component handling section 60 comprises a drawer 61 mounted on runners 62. Drawer 61 has a support frame which generally comprises an elongate U-shaped nest cavity frame 63 (Fig. 3). This frame 63 encloses a nest cavity shown generally as 64. Drawer runners 62 are provided with vertically-extending flanges 65 which serve to locate and provide a sliding edge for bosses 66 which extend from nest cavity frame 63 (Fig. 1). Thus, vertical movement of nest cavity frame 63 relative to drawer runners 62 is permitted by this arrangement, as will be described in more detail below. In order to limit the vertical movement of nest cavity frame 63, however, a stopper plate 67 is provided which is attached to the underside of the nest cavity frame 63 and which is wider than the frame 63 such that it will abut the underside of the horizontal section of each right-angled drawer runner 62 when the frame 63 reaches its upper limit of travel.

On each uppermost corner of the U-shaped nest cavity frame 63 is mounted an image sheet locator 68 which serves to retain the printed transfer sheet 200 in position during the transfer process. Each locator 68 may simply be a spring-loaded clamp. Means may also be provided on the nest cavity frame 63 and on the transfer sheet 200 to ensure correct location and orientation of the sheet, such as appropriate use of indicators, pins, arrows or the like on one or both components.

In the bottom surface of U-shaped nest cavity frame 63, on bearing support plate 69, are mounted two linear bearings 70. Slidably mounted in these bearings 70 is the nest support structure 80, which has a generally I- shaped longitudinal section (Fig. 3) formed by lower pressure plate 81 , two connecting pillars 82 and nest support plate 83. Four compression springs 84 are mounted between pressure plate 81 and the base of the U-shaped nest cavity frame 63, and their function will be explained in more detail below.

Also provided on nest cavity frame 63, in heat communication with nest support plate 83 when in its lower position relative to the frame, is a heat sink 71.

On top of nest support plate 83 is mounted component nest 86, which serves to locate and act as a mechanical support for component 100 to prevent distortion during the image transfer process. Nest 86 is specifically designed and manufactured for a particular component, and may have specific thermal characteristics relevant to that particular component, as discussed in the introduction.

In preferred embodiments, the nest is constructed on a base plate to which there is screwed an aluminium nest support 15 mm tall, shaped to follow the inside surface of the component with a uniform 5 mm gap. The gap is filled with nest material comprising an epoxy resin containing 25% by volume of Spheriglass E22/400 (available from Minnesota Mining and Manufacturing Co.), and cured at 100 °C for a period of 2 hours. This gives a durable, rigid nest with optimum thermal properties. The nest 86 is temperature-controlled via nest support plate 83 and air-cooled heat sink 71 to ensure consistent results, regardless of intensity of use, and to allow safe handling by operators when changing nests for different component types.

With reference to Fig. 3, between the transfer sheet locators 68 and the pressure pad 46 there is provided a stripper plate 90. The stripper plate 90 is mounted directly onto two actuating solenoids 92 which serve to move the stripper plate in a vertical direction. The plate is provided with an aperture 93 through which pressure pad 46 projects in use, as will be described in more detail below.

In order to provide a cooling air current through the apparatus when necessary, a cooling fan 95 is provided which draws air through the apparatus from an intake grille (not shown) in the front of the apparatus. In addition, the apparatus is provided with a pressure pad access aperture 96, to facilitate changing of the pressure pad 46 when necessary. Levelling feet 97 are also provided.

The apparatus is operated by means of a control panel (not shown) which is provided with status lamps, and Start and Cancel buttons. An audible alert may also be provided. A control module may be provided to control the various functions of the apparatus.

The operation of the image transfer apparatus will now be described. Once the power is switched on, the apparatus will wait for an operator to begin the warming-up process by pressing either the Start or the Cancel button. Whilst the apparatus is reaching temperature, the operator is able to open the drawer 61 and insert the correct nest 86 for the component 100 to be processed, together with the component 100 itself. Finally, the transfer sheet 200 is located in transfer sheet location devices 68, image down, with the image in the correct orientation and the drawer is closed.

The operator will then need to press the Start button to begin processing, and the drawer 61 will be latched. Alternatively, the apparatus can be reset and the drawer 61 opened at this stage by pressing the Cancel button. As will be evident from the description of operation of the apparatus below, there are various operating parameters involved, such as pad temperature, pre-heat time, contact time, cooling time, etc. In one embodiment, these parameters may be set in the factory and be fixed. In that case, the parameters are preferably optimised for the range of components that the apparatus is likely to encounter. In an alternative embodiment, the operating parameters can preferably be altered depending on the particular characteristics of the component or the coating being applied. These parameters may be adjusted manually by the operator via an interface provided on the apparatus, possibly in accordance with data or instructions provided with the component or the transfer sheet layer.

In accordance with another aspect, however, the nest 86 (which is specific to the component being processed) is provided with means for identifying to the apparatus the type or model of component. Alternatively, the apparatus may be able to recognise the component from one or more features of the component itself. Any feature of the component or nest which is designed to indicate to the apparatus the type or model of component can be regarded as a "machine recognisable feature".

In either case, the apparatus may be provided with some form of optical or visual recognition system which is able to identify one or more features of the component or nest. Alternatively, and more simply, a code for the particular component may be provided on the nest or component. This could again be in the form of optically- or visually-recognisable features, such as a barcode for example, or alternatively features such as a particular arrangement of metal contacts, one or more magnetic strips, notches, projections, pins or holes. Once determined, the code can then serve as the coordinates in a look-up table to establish the process parameters. A single code may serve to designate one, some or all of the various process parameters.

If appropriate, therefore, once the Start button is pressed and the particular product has been identified, the process parameters are obtained and loaded into the process. Obviously, as many different process parameter combinations may be stored in the apparatus as the number of different components which the apparatus is designed to be used with.

Once the pad 46 has been heated to the desired temperature, lifting mechanism 20 acts to cause lifting plate 23 to rise and contact pressure plate 81. This in turn presses against the compression springs 84 causing nest cavity frame 63 and stopper plate 67 to rise along with the nest support structure, bosses 66 moving vertically relative to drawer runner flanges 65. Stripper plate 90 may also be moved upwards by the nest cavity frame 63 as it rises. When the stopper plate 67 contacts the underside of the drawer runners 62, further movement of nest cavity frame 63 is halted. This is the pre-heat position of the device, for pre-conditioning the transfer sheet 200 and the surface of the component 100 by means of radiant heating to soften the transfer sheet. In this position, the transfer sheet 200 is preferably between 1mm and 3mm from the heated pad 46, and more preferably within 2mm. These spacings optimise the pre-conditioning of the transfer sheet 200.

The device is held in the pre-heat position for a predetermined time in accordance with the operating parameters. A time of approximately 5-30 seconds may be sufficient. Once this time has elapsed, the lifting mechanism 20 continues to lift, which causes the springs 84 to be compressed as the nest support structure 80, component nest 86 and component 100 then begin to move upwards relative to the nest cavity frame 63 in linear bearings 70.

The nest support plate breaks contact with the heat sink 71 and the component 100 presses into transfer sheet 200, and in turn both the component 100 and transfer sheet 200 are pressed into the pressure pad 46. Operation is again paused here whilst the predetermined contact time elapses. A suitable contact time may be in the region of 50-90 seconds.

The pre-conditioning of transfer sheet 200 allows the sheet to mould itself to the form of the component and exclude air from between the surfaces.

During this time, the heat from the resilient pad 46 further warms the transfer sheet 200 and the inks printed on it, and also heats the lacquer on the component, thereby allowing the inks to migrate into the lacquer from the transfer sheet. The temperature at the component to transfer sheet interface may range from 100-140 °C depending on the thermal characteristics of the lacquer and the component material, and the contact time. Once the contact time has elapsed, the stripper plate solenoids 92 are energised which causes the stripper plate 90 to clamp the transfer sheet 200 to the top surface of nest cavity frame 63 and to push the frame 63 downwards against springs 84. At the same time, the lifting mechanism 20 lowers, and therefore the nest support structure 80 lowers. Thus, the transfer sheet and component are withdrawn from the pad 46, the stripper plate 90 helping to prevent the transfer sheet sticking to the pad, and the nest support structure 80 and nest cavity frame 63 return to their lowered positions with springs 84 uncompressed. The stripper plate solenoids 92 are then de-energised. At this point, nest support plate 83 is in its lowered position in contact with heat sink 71. This is the cooling position, and operation is paused again while the cooling time elapses.

During the cooling time, fan 95 is operated, to draw air over the heat sink 71 , nest support plate 83, nest 86 and component 100. In use, the nest 86 may operate in the temperature range of 40-70°C, and it is preferably cooled to 50 °C or lower.

Optionally, an air deflector (not shown) may be provided which is able to slide between the resilient pad 46 and the transfer sheet 200 during the cooling operation, to shield pad 46 from the cooling air current. This has two benefits. Firstly, cooling of the component 100 and nest 86 is optimised as the air flow can be more accurately directed towards them, and secondly, heat is not unnecessarily lost from pad 46 during this operation so that time is not wasted in re-heating the pad up to temperature before the next component can be processed. The deflector may be movable under the action of one or more solenoids and/or springs, or an electric motor.

Also, a resilient cooling pad (not shown) may be provided, and this could be located on the underside of the air deflector. Once the air deflector and cooling pad are in place for the cooling operation, the lifting mechanism 20 may raise the nest support structure 80 and nest cavity frame 63 so that the transfer sheet 200 and component 100, which are still in contact with one another, become pressed against the cooling pad. This serves to cool the component 100 and nest 86 in a more efficient manner than simply by means of a cooling flow of air.

Once the cooling time has elapsed, the fan 95 is switched off. If appropriate, the lifting mechanism lowers the component and nest to the lowered position. The air deflector, and cooling pad if fitted, may be retracted at this point also. Alternatively, the deflector may stay in position until the next component is installed and the drawer closed again, so that heat loss from the pad 46 is further minimised.

The drawer is then unlocked, and the used transfer sheet 200, decorated component 100 and nest 86 may be safely removed by the operator. The machine is then ready for the cycle to be repeated. Fig . 4 shows a block diagram of the main features of the image transfer apparatus, which is useful for showing the functional relationship between the various components. Where components have already been referred to above, the same reference numerals are given.

Controller board 300 includes a cycle count display 301 and an indication 302 of the number of hours of operation of the apparatus. Mains power (e.g. 240V a.c.) enters the apparatus via on/off switch and fuse 303 and filter 304. Power is then supplied to heater pack 40 via over- temperature cut-out 305 and relay 306.

The mains power supply is transformed to 24V d.c, which supplies controller 300 via latching relay 307. A cover switch 308 is provided, which turns off the apparatus should the cover be opened. Start and Cancel switches 309 and 310 together with indicator lamps are also provided, together with a power indicator lamp 311. Cooling fan 95 and stripper plate solenoids 92 are also shown in the figure.

Scissor lift 21 is powered by means of actuator 312. A four-position opto-switch sensing system 313 is provided to sense the lift when it is in the following positions: load/unload (i.e. drawer open), down (drawer closed), pre-conditioning and image transfer.

Component nest 86 is identified by a four micro-switch parameter sensing system 314, and this permits 16 different process parameter combinations to be available, the optimum combination being selected depending on the characteristics of the component concerned.

The various functions of the apparatus as described above may be controlled by an internal controller having a microprocessor and a memory. There may also be provided an operator interface on the exterior of the machine, such as a display and keypad. Alternatively, the apparatus may be controlled by software running on a conventional computer which is connected to the apparatus. The computer may also be used to acquire an image from a source, to manipulate the chosen image to fit a particular component, to add any additional text or graphics, to display a representation of the completed image on the component, and to finally print the completed image onto transfer sheet in reverse format suitable for a transfer, such that the transfer sheet is printed and ready for the transfer process.

The apparatus may be provided with diagnostics which alert maintenance personnel to rapidly fault find errors through coded signals. The image on the transfer sheet or carrier sheet 200 may be produced by a variety of different printing techniques, including electrophotography, mass transfer printing, ink jet printing, melt or wax transfer printing, and dye diffusion thermal transfer printing. Appropriate carrier sheet material will need to be used in each case. In a preferred embodiment, a dye diffusion thermal retransfer printing process using a retransfer intermediate sheet may be adopted. A retransfer intermediate sheet typically comprises a supporting substrate having a dye- receptive coating, or receiver layer, on one surface thereof (as described in EP-A-409514), with the other surface optionally carrying a coating to improve the frictional, release or static properties of the sheet during printing. This surface also preferably carries a heat-resistant back coat, as described in WO98/02315. The substrate may comprise paper, or a polyolefin-coated paper, but preferably comprises a laminated material prepared by laminating an opaque, voided polypropylene film to a cellulose paper base material, such as disclosed in JP 06-84119. The voids in the polypropylene layer improve the compliance of the sheet. Suitable dyes are disclosed in EP-A-209991 , EP-A-218397, EP-A-

247737 and EP-A-312211. Suitable thermal transfer printing dyesheets are disclosed in EP-A-409514 (referred to above), EP-A-547893 and W094/29116.

Figure 5 illustrates a preferred arrangement of the present invention. In the arrangement shown in Figure 5, a transfer sheet support means 400 is provided which comprises a generally box-like container of a U-shaped cross-section. The transfer support means 400 includes a base 401 from which two side walls 402 extend. A generally 'T'-shaped component support means 403 is provided which comprises an upper component carrying plate 404 located within the transfer sheet support means 400 and a lower flange 405 located below the transfer sheet support means 400. The component carrying plate 404 supports a component nest as described above and means are provided to connect the component carrying plate 404 and the lower flange 405 of the component support means 403. The upper edges of the side walls 402 of the transfer sheet support means 400, i.e. the edges of the side walls 402 furthest from the base 401 , are formed with an inwardly projecting lip 406 which extends substantially around the four sides of the transfer sheet support means 400. The lip 406 defines an aperture 407 through over which a transfer sheet (not shown) can be placed and through which the component 408 can be pushed. A stripper plate 409 is provided which is hingedly attached to the transfer sheet support means 400. The stripper plate 409 generally overlies the upper surface of the lip 406 of the transfer sheet support means 400 and is sized and shaped to generally match the lip 406 and also provide an aperture through which the component 408 can be pushed. The stripper plate 409 can be hinged to an open position so that a transfer sheet can be loaded onto the transfer sheet support means 400 and supported by the lip 406. The stripper plate 409 can then be hinged to a closed position, as shown in Figure 5, in which the periphery of the transfer sheet is sandwiched between the upper surface of the lip 406 and the lower surface of the stripper plate 409. The image transfer apparatus is further provided with a catch 410 which is rotatably attached to the stripper plate 409. The catch is arranged for selective engagement with a lug 411 formed on the component support means 403. The lug 411 comprises a generally cylindrical element which extends through an elongate aperture 412 formed in a side wall 402 of the transfer sheet support means 400.

The catch 410 is provided to selectively lock the stripper plate 409, and consequently the transfer sheet support means 400, to the component carrying means 403 and thus selectively prevent relative movement of the two support means. The lug 411 can be engaged by a first portion of the catch 410 or by a second portion of the catch 410 so that the component support means 403 and the transfer sheet support means 400 can be selectively locked at a first distance from each other and at a second distance from each other as will be explained in more detail below.

In use, the stripper plate 409 is hinged open and a transfer sheet (not shown) is loaded onto the upper surface of the lip 406 of the transfer sheet support means 400. The stripper plate 409 is then hinged to a closed position in which the transfer sheet is retained between the stripper plate 409 and the lip 406 of the transfer sheet support means 400. With the transfer sheet in position between the stripper plate 409 and the lip 406, a first portion of the catch 410 engages with the lug 411 of the component support means 403. Engagement of the catch 410 in this position prevents the two supports from moving apart and ensures that the stripper plate 409 is held in its closed position.

Figure 5 shows the apparatus in its initial position when the image press is started. The component support means 403 is in a first position in which it is spaced at a distance from the heating means (not shown) located above. The transfer sheet support means is also in its first position with the transfer sheet located at a distance from the heating means. In this position, the lug 411 of the component support means 403 extends through a lower portion of its elongate aperture 412. As can be seen, a number of similar lugs and elongate apertures are provided which serve to guide relative movement of the two support means. Only one lug, lug 411 , is selectively engaged by the catch 410.

Starting of the image press activates the lifting mechanism (not shown) which applies a force to the lower flange 405 of the component support means 403. Spring means (not shown), such as a number of helical springs, are provided between the upper surface of the lower flange 405 of the component support means 403 and the lower surface of the transfer sheet support means 400 to bias the two support means apart. The force applied to the lower flange 405 of the component support means 403 by the lifting mechanism acts to lift both the component support means 403 and the transfer sheet support means 400 due to the resilience of the spring means. The two support means therefore move together until the transfer sheet support means 400 reaches its second (pre-conditioning) position. The transfer sheet support means is stopped in this position by a stop bar 413 attached to the transfer sheet support means 400 which abuts against the underside of side rails 414. When the stop bar 413 abuts against side rails 414 further movement of the transfer sheet support means is prevented and the transfer sheet is located in close proximity to the heating means so that it can be preheating prior to image transfer. The lifting mechanism however continues to apply further force to the component support means 403 so that the spring means compress and the component support means 403 begins to move relative to the transfer sheet support means 400. This relative movement continues until the component support means 403 reaches its second (pre-conditioning) position in which the component 408 is close to but located beneath the transfer sheet. This is the position shown in Figure 6 and the two support means are maintained in this position for a sufficient time to preheat the transfer sheet and the component 408. As can be seen in Figure 6, the relative movement of the component support means 403 and the transfer sheet support means causes the lug 411 to be released from its initial engagement with the first portion of the catch 410.

Once preheating is complete, the lifting mechanism applies further force to the component support means 403. This further force causes further compression of the spring means which causes movement of the component support means 403 relative to the transfer sheet support means 400. The resulting movement causes the component 408 to move through the transfer sheet to the position shown in Figure 7. In this position the transfer sheet is forced into engagement with the heated resilient pad (not shown). The transfer sheet stretches or otherwise deforms around the component 408 and is sandwiched between the component 408 and the resilient pad.

In the position shown in figure 7, with the component 408 pressed into the resilient pad and the transfer sheet sandwiched between the component 408 and the resilient pad, the catch 410 moves so that a second portion of the catch 410 engages the lug 411. This again enables the two support means to be held relative to each other but when the lug 411 is engaged by the second portion of the catch the transfer sheet is held against the component 408 and the spring means are held in compression. After a sufficient period of time has elapsed to allow the image on the transfer sheet to be transferred to the component, the lifting mechanism is then lowered. The catch 410 holds the component support means 403 and the transfer sheet support means 400 together, thus lowering of the lifting mechanism causes both support means to move together away from the heating element and towards a position in which the transfer sheet and the component 408 can cool. The catch therefore enables the transfer sheet and the component 408 to be held together both as they lowered and also during the cooling process which can improve the quality of image transfer. The lifting mechanism lowers until the two support means are both in their cooling position as shown in Figure 8. In this position the component support means 403 is in its first position, i.e. its position prior to loading of a transfer sheet. The transfer sheet support means is however located below its first position since the spring means are held in compression by the catch 410. This enables the transfer sheet and the component 408 to be held in contact with each other. In this position cooling means, such as a fan, are provided to cool the transfer sheet and component 408 and also to cool other elements of the apparatus if desired.

Once cooling is complete the catch 410 is released from engagement with the lug 411 which allows the spring means to expand. Expansion of the spring means causes the transfer sheet support means 400 to move upwards and away from the component support means 403. The transfer sheet support means 400 returns to its first position which causes the transfer sheet, which retained by the stripper plate 409, to be separated from the component 408. The apparatus is then in the position shown in figure 9 in which the two support means located in their first positions, i.e. in the positions they were in before the image press was started. With the transfer sheet and the stripper plate now separated, the stripper plate 409 can be hinged to its open position and the transfer sheet and component 408 removed from the apparatus. The apparatus is then ready to be loaded with another transfer sheet and another component. Figure 10 shows a side view of a preferred form of the catch 410.

The catch 410 includes an upper arm 415 which is rotatably attached to the stripper plate. The catch includes a first portion 416 which can selectively engage a lug of the component support means so that the two supports are maintain at a first relative distance. The first portion 416 of the catch is used to engage the lug once the apparatus has been initially loaded with a transfer sheet. The catch in this condition serves to maintain the stripper plate in its closed position with the transfer sheet sandwiched between the stripper plate and the lip of the transfer sheet support means. The catch includes a second portion 417 which can also selectively engage the lug. The second portion 417 of the catch 410 engages the lug once the component has been pushed through the transfer sheet and into engagement with the heated resilient pad. In this condition, the catch 410 serves to hold the transfer sheet in engagement with the component during the image transfer process and also during the cooling process which occurs once the lifting mechanism has lowered.

Figures 11 to 14 show a preferred form of resilient heating pad. The pad 518 is generally block-shaped and is formed as a discretely moulded element. The pad 518 comprises an upper surface 519, a lower surface 520 and side walls 521 which extend around the edge of the pad 518. The side walls 521 of the pad 518 extend downwardly from the upper surface 519 of the pad 518 and are then stepped inwardly to provide a cutaway portion in the form of an overhang 522 at the edge of the pad 518. The overhang 522 extends around the entire perimeter of the pad 518 and provides space into which the pad material can expand when the pad 518 is compressed by a component.

A number of spaced supporting elements 523 are provided which extend into the space defined by the overhang 522. The supporting elements 523 assist in supporting the upper surface 514 of the pad 518 so that the upper surface 514 is maintained against, or in close proximity to, the heating element during preheating of the pad 518. The supporting elements 523 comprise a number of spaced cylindrical elements that extend downwardly from the underside 524 of the overhang 522 and terminate at a lower end generally at the level of the lower surface 520 of the pad 518. The support elements 523 are integrally formed from the resilient material of the pad 518. As can be seen in Figure 12, the supporting elements 523 are provided along two opposing sides of the pad 518 and are generally evenly spaced along the length of the pad 518.

As shown in Figure 13, in use the pad 518 is supported adjacent to, or against, the heating element (not shown) by a metal surround 524. the metal surround substantially encloses the pad 518 whilst leaving the lower surface 520 of the pad 518 exposed so that a component can be pressed into the pad 518. The metal surround 524 has a Z-shaped cross-section along two opposing sides of the surround 524. This cross-section includes a lower flange 525 which extends a short distance beneath the pad 518. As can be seen in Figure 13 the pad is arranged so that the support elements 523 are engaged with the lower flange 525 of the metal surround 524 and provide the only contact between the pad 518 and the metal surround 524 when the pad is not compressed by a component. In this position, the supporting elements 523 serve to maintain the upper surface 519 of the pad 518 in close proximity to, or in engagement with, the heating element (not shown). The pad 518 and the metal surround 524 are arranged so that the pad 518 does not fill the volume defined by the metal surround 524 but instead space is provided, firstly, in the form of a gap between the side wall 521 of the pad 518 and the metal surround 524, and secondly, in the form of the overhang 522 in the side wall 521 of the pad 518. This space provides a volume into which pad material can expand when the pad is compressed by a component 508.

Figure 14 illustrates the pad 518 in its deformed condition when compressed against the heating element by a component. In this condition the lower surface 520 of the pad deforms and, to some extent, wraps around the upper face of the component to provide improved image transfer. The material of the pad 518 is expanded outwardly towards the metal surround 524 and into the volumes defined by the overhang 522 and the gap 526 between the pad 518 and the metal surround 524. As can be seen, in the deformed condition of the pad 518, the supporting elements 523 are substantially "crushed" by the force of the expanding pad material.

Claims

Claims:

1. An image transfer apparatus for thermally transferring an image from a transfer sheet to a component, comprising a resilient pad, means for heating the resilient pad to a predetermined temperature, and means for supporting the component in use, wherein the component support means is movable in use from a first component position in which the component is spaced from the resilient pad, to an image transfer position in which at least part of the component is urged into engagement with the heated resilient pad through the transfer sheet such that the image on the transfer sheet is transferred to the component.

2. The apparatus of claim 1 , wherein the component support means is movable to a second component position intermediate the first component and image transfer positions, closer to the resilient pad than in the first component position.

3. The apparatus of claim 1 or 2, further comprising means for supporting the transfer sheet in use between the pad and the component.

4. The apparatus of claim 3, wherein means are provided on the transfer sheet support means for retaining the transfer sheet in use.

5. The apparatus of claim 4, wherein means are provided on the transfer sheet support means and/or on the transfer sheet to ensure correct location and orientation of the sheet.

6. The apparatus of any of claims 3 to 5, wherein the transfer sheet support means is movable from a first transfer sheet position in which the transfer sheet is spaced from the pad to a second transfer sheet position in which the transfer sheet is proximate to the pad.

7. The apparatus of claim 6, wherein the transfer sheet is between 1 mm and 3mm from the heated pad, or alternatively within 2mm thereof, when in the second transfer sheet position.

8. The apparatus of claim 6 or 7, wherein the apparatus is configured such that the component support means is movable in use to the image transfer position or second component position only at the same time as or after the transfer sheet support means moves to the second transfer sheet position.

9. The apparatus of claim 6, 7 or 8, wherein the transfer sheet support means remains in the second transfer sheet position whilst the component is moved to the image transfer position and into engagement with the resilient pad through the transfer sheet to effect the image transfer.

10. The apparatus of claim 9, further comprising a stripper plate which clamps the used transfer sheet to the support means as the support means moves back to the first position.

11. The apparatus of claim 2 and any of claims 6 to 10, wherein the component support means and the transfer sheet support means are arranged such that they are movable together from their respective first positions to their respective second positions, and the arrangement is such that the component support means is then movable relative to the transfer sheet support means to the image transfer position.

12. The apparatus of claim 11 , wherein the two support means are slidably connected to one another and are urged towards a particular relationship by means of one or more springs or the like.

13. The apparatus of claim 12, wherein the arrangement is such that, when both support means are in their first positions, a force acting on the component support means to move it to the second component position will also serve to move the transfer sheet support means to its second position, the spring bias maintaining the relative position between the two support means.

14. The apparatus of claim 13, wherein the apparatus further comprises means to stop the transfer sheet support means at its second position.

15. The apparatus of claim 13 or 14, wherein the arrangement is such that, when both support means are in their second positions, a force acting on the component support means causes that means to move relative to the transfer sheet support means towards the image transfer position, against the spring bias.

16. The apparatus of any of claims 3 to 15, wherein the transfer sheet support means comprises a generally U-shaped member, the transfer sheet being supported in use across the tops of the "U", a component cavity being defined within the "U".

17. The apparatus of claim 16, wherein the component support means is l-shaped in cross-section, with the central section of the "I" being slidably mounted in the bottom surface of the U-shaped transfer sheet support means, the component being supported in use on the upper flange of the "I", inside the component cavity.

18. The apparatus of claim 17 and any of claims 12 to 15, wherein the spring means is positioned between the underside of the "U" and the lower flange of the "I" such that the two support means are urged towards a position in which the upper flange is at its lowermost position inside the "U".

19. The apparatus of any of claims 3 to 18, further comprising a housing in which is mounted the resilient pad and heating means, and a drawer on which the component and transfer sheet support means are mounted, the drawer providing access to the support means in its open position for loading or unloading the transfer sheet and/or component.

20. The apparatus of any preceding claim, further comprising means to move the component support means between its three positions.

21. The apparatus of any of claims 3 to 19, further comprising means to move the transfer sheet support means between the two transfer sheet positions.

22. The apparatus of claim 20 or 21 , wherein the movement is provided by a lifting mechanism, such as a scissor mechanism, powered by an electric motor.

23. The apparatus of claim 22, wherein the lifting mechanism is adapted to provide a pressure of up to about 5.5 kg/cm² between the component and the resilient pad in use.

24. The apparatus of claim 19 and 22, wherein the lifting mechanism is mounted in the housing.

25. The apparatus of any preceding claim, wherein the pad is inherently resilient.

26. The apparatus of any preceding claim, wherein the pad is resilient by virtue of being resiliently mounted.

27. The apparatus of any preceding claim, wherein the pad is formed from silicone foam and aluminium.

28. The apparatus of any preceding claim, wherein the pad is between 4mm and 20mm in thickness.

29. The apparatus of any preceding claim, wherein the surface of the pad which contacts the transfer sheet in use is textured to reduce adhesion between the pad and the transfer sheet and/or component.

30. The apparatus of any preceding claim, wherein the heating means is adapted to heat the resilient pad to a temperature range of between 100°C and 240°C in use.

31. The apparatus of any preceding claim, wherein the means for supporting the component includes a nest, which serves to locate and act as a mechanical support for the component to prevent distortion during the image transfer process.

32. The apparatus of claim 31 , wherein the nest is adapted to locate and support a predetermined component.

33. The apparatus of claim 31 or 32, wherein the nest is provided with specific thermal characteristics which are dependent on the thermal characteristics of the component.

34. The apparatus of claim 31 , 32 or 33, wherein the nest is formed from unfoamed silicone resin, at least in the region which contacts the component in use.

35. The apparatus of any of claims 31 to 34, wherein the nest material is formed over an internal support which preferably follows the contours of the component.

36. The apparatus of claim 35, wherein the internal support material has a higher thermal conductivity than the nest surface material.

37. The apparatus of claim 35 or 36, wherein the internal support is made from a metal, or from metal-filled resin.

38. The apparatus of any of claims 31 to 37, wherein the nest material is of substantially uniform thickness.

39. The apparatus of claim 38, wherein the nest material is less than 8mm in thickness, and more preferably between 2 and 4mm in thickness.

40. The apparatus of any of claims 31 to 39, wherein the nest is temperature-controlled, preferably by means of being in heat communication with a heat sink.

41. The apparatus of any of claims 31 to 40, wherein the nest is provided with means identifying at least one component characteristic or at least one process parameter.

42. The apparatus of claim 41 , wherein the identifying means comprises one or more notches or projections on the nest.

43. The apparatus of claim 41 or 42, wherein the apparatus is provided with means for reading or interpreting the identifying means.

44. The apparatus of claim 43, wherein the reading means comprises one or more micro switches.

45. The apparatus of any of claims 41 to 44, wherein the identifying means provides information about the component or the process parameters in code form.

46. The apparatus of claim 45, wherein the code serves as the coordinates in a look-up table to establish the process parameters.

47. The apparatus of any of claims 31 to 42, wherein the apparatus is provided with means for recognising the component or nest from one or more features thereof.

48. The apparatus of claim 47, wherein the apparatus further includes an optical or visual recognition system which is able to identify one or more features of the component or nest.

49. The apparatus of any preceding claim, further including cooling means for cooling the component after image transfer.

50. The apparatus of any preceding claim, wherein the apparatus is controlled by an internal controller having a microprocessor and a memory.

51. The apparatus of any preceding claim, wherein the apparatus is controlled by software running on a computer which is connected to the apparatus.

52. A system comprising an image transfer apparatus in accordance with any preceding claim and a computer having software adapted to control the image transfer apparatus.

53. The system of claim 52, wherein the computer is adapted to acquire an image from a source.

54. The system of claim 52, wherein the system further comprises a scanning means for providing a representation of the image to be applied to the component.

55. The system of claim 53 or 54, wherein the computer is adapted to manipulate the image to put it in a form suitable for application to the component.

56. The system of any of claims 52 to 55, further comprising a printer, under control of the computer, which is adapted to print the image on a transfer sheet suitable for use in the image transfer apparatus.

57. A method of transferring an image from a transfer sheet to a component in an apparatus comprising a resilient pad, means for heating the resilient pad to a predetermined temperature, means for supporting the component in use, and means for supporting the transfer sheet in use between the component and resilient pad, the method comprising the steps of placing the component on the component support means, placing the transfer sheet on the transfer sheet support means, heating the resilient pad to the predetermined temperature, and moving the component from a first component position in which the component is spaced from the resilient pad, to an image transfer position in which at least part of the component is urged into engagement with the resilient pad through the transfer sheet, such that the image on the transfer sheet is transferred to the component.

58. The method of claim 57 and further comprising the step of moving the transfer sheet from a first transfer sheet position in which the sheet is spaced from the pad to a second transfer sheet position in which the sheet is proximate to the pad.

59. The method of claim 57 or 58, wherein the method further comprises the step of pre-conditioning the transfer sheet and/or component prior to image transfer.

60. The method of claim 58 or 59, wherein the method further comprises the step of moving the component to a second component position intermediate the first component and image transfer positions, at the same time as or after the transfer sheet is moved to the second transfer sheet position, proximate to the resilient pad..

61. The method of any of claims 57 to 60 and further comprising, following the image transfer step, the steps of withdrawing the component to the second component position, and subsequently withdrawing the component and transfer sheet to their respective first positions.

62. The method of any of claims 57 to 61 and further comprising the step of cooling the component after image transfer.

63. The method of any of claims 57 to 62 and further comprising the step of pre-treating the component prior to the application of the image.

64. The method of claim 63, wherein the step of pre-treating the component comprises applying a layer of lacquer to the surface of the component.

65. An image transfer apparatus substantially as hereinbefore described with reference to the accompanying drawings.

66. A system substantially as hereinbefore described with reference to the accompanying drawings.

67. A method of transferring an image substantially as hereinbefore described with reference to the accompanying drawings.

68. A heating pad arrangement for use in an image transfer process, said arrangement including a generally block-shaped resilient heating pad which has an upper surface, a lower surface and side walls, wherein at least a portion of the edge of the pad is formed with side walls that extend from the upper surface but are then stepped inwardly to provide a cutaway portion in the form of an overhang.

69. The heating pad arrangment as claimed in claim 68, wherein the overhang extends substantially around the perimeter of the pad.

70. The heating pad arrangment as claimed in claim 68, wherein the overhang extends along two opposing edges of the pad.

71. The heating pad arrangment as claimed in any of claims 68 to 70, wherein one or more supporting elements are provided which extend into the space defined by the overhang and act in use to maintain the upper surface of the pad against, or in close proximity to, a heating element.

72. The heating pad arrangment as claimed in claim 71 , wherein the supporting elements comprise a number of spaced resilient projections that extend from the underside of the overhang and terminate generally at the level of the lower surface of the pad.

73. The heating pad arrangment as claimed in any of claims 68 to 72, further including a generally rigid surround which supports the resilient pad whist allowing the under side of the pad to remain exposed so that a component can be pressed into the pad.

74. The heating pad arrangment as claimed in claim 73, wherein the surround includes one or more flanges that extend beneath the pad in use to support the pad.

75. The heating pad arrangment as claimed in claims 73 or 74, wherein the surround and the pad are sized such that space is defined between the pad and the surround into which the pad can expand when compressed by a component.

76. The heating pad arrangment as claimed in claims 75, wherein the pad is substantially supported on supporting elements which maintain the upper surface of the pad in close proximity to the heating element when the pad is unloaded, and which deform to enable the pad to expand when the pad is loaded, said supporting elements being supported by the surround.

77. An image transfer system wherein an image is transferred from a transfer sheet onto a component by pressing the transfer sheet onto the component using a heated resilient pad.