The present invention relates to apparatus for transferring foil, particularly metallic foil, on to separate sheets of substrate material such as photocopies or laser printed copies on paper, card or plastic.

Hitherto, this has been done by the use of a machine known as a pouch laminator, utilising specially cut and manufactured sheets of foil. One sheet of foil is placed on top of the sheet of paper, both are then together placed between two sheets of card about 200gm thick, the combination then being passed through the heated rollers of the pouch laminator. The combination is then picked up by hand as it exits the laminator, the top and bottom cards are removed, the spent foil is removed from the paper and is then discarded, leaving only these areas which are printed covered by foil.

The above steps constitute a lengthy process suitable only for production of a few sheets at any one time.

It is therefore the aim of the present invention to provide improved apparatus which requires minimal operator intervention, thus enabling faster and more efficient operation.

According to the present invention there is provided apparatus for transferring foil to separate sheets of substrate material, the apparatus comprising a foil dispensing mechanism, a feed mechanism for feeding sheets of substrate material sequentially into the apparatus, at least one pair of opposed heated rollers, and means for conveying the substrate material and the foil together through the nip of said heated rollers.

Preferably, the feed mechanism includes a feed tray incorporating a device for preventing two sheets being fed into the apparatus at the same time (hereinafter referred to as a

"double sheet stopping device". This device is preferably a self-compensating spring/lever arrangement and may incorporate manual adjustment means. Immediately adjacent the feed tray there is located one or more feed rollers, to feed one sheet at a time into the apparatus. The double sheet stopping device is located directly beneath the feed roller(s). Additionally, an arrangement is also provided in case it should be necessary to adjust the flow manually.

Conveniently, the conveying means comprises an endless belt which preferably is manufactured from a material able to withstand high temperatures and having good heat conductivity (the rollers are heated to approximately 155 degrees C.) The belt passes around a number of spaced apart rollers at least one of which drives the belt, and therefore it is preferred that the side of the belt which touches these rollers is manufactured with a rough surface, to give maximum grip. The other side may be either smooth, or patterned to impart a specific design to the foil being transferred to the substrate. To this end, there may be provided a number of endless belts, each incorporating a different pattern.

The tension in the endless belt may be adjusted by adjusting the position of one of the rollers (hereinafter referred to as the tension roller) , and there may also be included a mechanism for finer adjustment of the tension in the endless belt.

The foil dispensing mechanism comprises a holder for a roll of foil, such that the foil may be continuously dispensed from said roll. The foil passes over a foil tension roller, the position of which may be adjusted to adjust the tension in the foil. There may also be provided a mechanism for finer adjustment of the foil tension.

Conveniently, there are four rollers, arranged in two adjacent, opposed pairs. The first pair comprises heated rollers and the second pair comprises unheated presssure rollers.

At the exit end of the apparatus, there is provided a spent foil collecting mechanism in the form of a spool onto which the spent foil is automatically wound, the apparatus including a device which keeps a reasonable tension on the spool such that the spent foil roll does not swell up and therefore frequent emptying of the spool is not necessary.

When the substrate material and the foil exits from the heated rollers, the foil is essentially adhered to the substrate, and needs to be gently peeled off. The strength with which the foil adheres to the substrate is greater the greater the temperature of the heated rollers. The temperature of the heated rollers is sometimes increased slightly higher than normal in order to impart extra shine to the foiled covered areas on the substrate.

The apparatus therefore includes a separator mechanism which exerts a very gentle peeling effect on the substrate/foil combination, such as not to damage the finished product. This separator mechanism is located at the exit end of the apparatus, just beneath the spent foil collecting spool.

Occasionally, and particularly when the temperature of the heated rollers has been increased slightly, as described above, unwanted flakes of foil may adhere loosely to the substrate, after the separation has taken place. To alleviate this problem, the apparatus preferably includes a cleaning unit, located adjacent the separator, and comprising a rotating brush, pressure adjustment means and extraction means to remove the unwanted foil flakes into a waste collection bag. The substrate is conveyed through the cleaning unit by means of a thin, semi-soft endless belt which passes around feed and delivery rollers located at the entry and exit ends respectively of the cleaning unit. The pressure adjustment means, which comprises a roller located directly beneath the rotating brush, is conveniently adjustable both vertically and

horizontally, so that pressure may be exerted on any desired section of the substrate.

In most cases, the apparatus would be used to apply foil to the printed areas of photocopies or laser printed copies on either paper or card. These tend to come out of the photocopier or printer slightly curled, due to the high temperature inside the photocopier/printer. To alleviate this problem at the same time as applying the foil, the apparatus preferably comprises a de-curling mechanism. This is conveniently located between the two pairs of rollers, to de-curl the substrate as it passes therethrough.

The apparatus also preferably includes a delivery tray, for collecting the separated or separated/cleaned foiled sheets.

Thus, the apparatus provides an almost completely automatic process for applying foil continuously to consecutive sheets of substrate.

According to a further aspect of the present invention there is provided a method of substantially automatically applying foil to a substrate material, the method comprising feeding a continuous length of foil together with separate, consecutive sheets of substrate, through the nip provided by at least one pair of opposed rollers, and heating said rollers to cause the foil to be applied to the substrate.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 illustrates apparatus according to the present invention,

Figure 2 illustrates apparatus according to the present invention, modified by inclusion of de-curling and

cleaning mechanisms, and

Figure 2a is a vertical section through the de-curling mechanism of the apparatus shown in Figure 2.

Referring to Figure 1 of the drawings, apparatus 10 according to the present invention comprises two opposed pairs of heated rollers 12,14 and 16,18 and an endless belt 20 arranged to pass through the nips created by said roller pairs, and around three rollers 22, 24 and 26. Rollers 22 and 24 drive the endless belt 20, and roller 26 is a belt tension roller, adjustably mounted on a bar 28. A finer adjustment of the belt tension is provided by device 26a. Thus, the tension in the belt may be adjusted by moving the tension roller 26 along the bar 28, and/or operating the fine tension adjuster 26a.

A foil roll 30 is mounted on a vertical support 32, the free end of .the foil being passed over a pre-tensioned foil tension roller 34 and is picked up by the endless belt as it passes around roller 22.

At the entry end of the apparatus there is a feed tray 36 for the stacked individual substrate sheets (eg laser printed copies or photocopies), the feed tray being inclined generally downwardly towards the entry of the apparatus, where there is mounted a series of feed rollers 38 which are driven from belt drive roller 22, via pulley 40. Directly beneath the feed rollers 38 there is located a double sheet stopping device 42, comprising a self compensating spring/lever arrangement designed to prevent more than one sheet at a time being picked up by the feed rollers 38.

Once picked up by the feed rollers, each single substrate sheet is married with a section of the continuously fed foil, and the two together pass through the nip 13, 17 between each pair of

heated rollers. This heat and pressure treatment causes the foil to be applied to the printed areas of the printed or copied substrate, fusing with the toner.

Upon exiting the apparatus, the foil is separated from the substrate sheet by means of a separator 44, the finished, foiled sheet dropping into collection tray 46 and the spent foil being taken up and wound onto a spent foil collection spool 48 which is driven from roller 24 via pulley 49. Alternatively, the pulley 49 may be driven by a separate motor (not shown) .

The endless belt 20 picks up the foil and the sheets of substrate, and conveys them together through the nip 13, 17 between the rollers 16, 18 and 12, 14, at which point the foil is caused, by the heat and pressure to adhere to the toner on the substrate photocopy or laser printed copy, and from the rollers, on to the separator 44.

The endless belt 20 is made of a material capable of withstanding in excess of 180 degrees centigrade, and has one side rough to offer maximum grip to the drive rollers and has the other side either very smooth, to effectively "iron" the foil onto the substrate, or patterned to cause the pattern to transfer onto the foiled areas of the finished substrate.

Referring now to Figure 2, this embodiment of the apparatus incorporates all of the features of Figure 1 and in addition includes two additional features - a de-curling device 50, located between the two roller pairs 16, 18 and 12, 14, and a cleaning unit 60, located between the wedged-shaped separator 43 and the collection tray 46.

The de-curling device 50 is included to counter the problem of curling of the substrate sheets, which tends to occur because of the high temperatures inside laser printers and photocopiers. This device includes a heating element 50a

located directly above the belt 20 and a support structure 50b located directly beneath the belt, aligned with the heating element 50a. The combined effects of the passage through the heating element 50 and the second roller pair 12, 14, causes any curling of the substrate sheet to be eliminated. The de- curling device 50 is shown in more detail in Figure 2a, where the belt support 50b is shown shaped concave, and beneath the heater element 50a there is a convex shaped piece of metal 50c, running along the with of the heater, this metal piece being urged towards the concave support by means of a spring 50d.

Occasionally, in order to give extra shine to the printed matter on the substrate laser printed copy or photocopy, it is necessary to increase the temperature of the heated rollers 12,14,16,18 slightly higher than normal. As a result, the foil fuses onto the toner more strongly and with the correct amount of pressure, results in glaring shine to the surface of the printed matter. One drawback is that the foil also adheres quite strongly to the unprinted areas of the substrate, such that the two have to be separated very gently, using a peeling action. The separator 43 extend across the entire width of the apparatus, and is mounted at each side to the frame (not shown) , and exerts a gentle but effective peeling action, causing the spent foil to be diverted upwards onto the spent foil spool 48 and the printed matter to be directed downwards into the collection tray 46.

When operating the apparatus at these slightly higher temperatures, extra unwanted foil sections (flakes) adhere loosely to the substrate. To remove these, there is provided a cleaning and extraction unit, designated generally by 60. This comprises a thin and semi-soft endless belt 74, driven by rollers 66, 68. A rotating brush 71 is located directly above belt 74, and presses against support roller 64 located directly beneath the belt 74 (roller 64 is mounted so that it can easily be adjusted for pressure even when the machine is running, and is adjustable both horizontally and vertically, so that

pressure can be applied to any desired area of the printed copy) . An extraction unit 62 in the form of a hood covers the rotating brush 71 and the immediately adjacent area, and allows the flakes of foil removed by the brush 71 to be collected into a waste bag, via a vacuum applied to the hood, thus stopping it going into the atmosphere and being a health hazard. The lower edge of the hood 62 is designed so as to allow smooth movement of the substrate through its underneath section. The cleaned, foiled copy exits from between the rollers 68, 70 and drops into the collection tray 46.

To operate the apparatus, the sheets of substrate are loaded into the feed tray 36 (this is designed to hold about 150 sheets of 90gm paper) , and the temperature of the rollers is brought to approximately 150-155 degrees centigrade.

The feed start button is switched on and the paper starts to feed automatically, one sheet at a time.

The paper is then carried forward underneath the foil 31, on top of which is the endless belt 20 with its smooth/patterned side pressing on the foil 31 while passing through the rollers 16, 18, 12, 14. The spent foil then rolls onto the spool 48, and this in itself may be enough to separate the spent foil from the paper, or a separator 44, 43 may be included to assist in this operation.