Device That Is Configured To Handle Foil For Use In A Printing Process

Abstract

A device for handling foil for use in a printing process during which portions of a layer of the foil are transferred to a substrate comprises a foil input unit for inputting at least one foil web to the device, a number of rotatable shafts and bars for directing the at least one foil web to the printing press and retrieving at least one used foil web from the printing press, an arrangement for controlling operation of the device, and a web tension feedback unit for detecting at least one characteristic related to an actual web tension during operation of the device so as to realize web tension control by adjusting motion and/or positioning of at least one of the rotatable shafts and bars in case the characteristic appears to deviate from a reference related to a set web tension.

Claims

1. A device comprising: a foil input unit with a foil web; a shaft and bar arrangement providing unused foil web to a printing press and retrieving used foil web from the printing press; a web tension feedback unit to detect a characteristic related to foil web tension; and a controlling arrangement configured: to receive the characteristic related to foil web tension from the web tension feedback unit; to identify an operable deviation between the characteristic and a reference; and to control the shaft and bar arrangement in response to the identification of the operable deviation.

2. The device of claim 1, wherein the foil web is used in a printing process during which transfer portions of a layer of the foil web are transferred to a substrate to be printed, the device arranged at a printing press having a printing area designed to let such a printing process take place during operation of the printing press; wherein the shaft and bar arrangement comprises rotatable shafts and bars arranged upstream and downstream of the printing area; and wherein the web tension feedback unit is selected from the group consisting of: a visual inspection unit that is arranged and configured to visually inspect an actual pattern of removed transfer portions in a length of used foil web, wherein the reference represents a reference pattern of removed transfer portions; a pressure detection unit that is arranged and configured to detect pressure exerted by the foil web on at least one area of at least one of the rotatable shafts and bars, and wherein the reference represents a reference pressure; and a position detection unit that is arranged and configured to detect a position of at least one of the rotatable shafts and bars with respect to a carrier frame, wherein the at least one of the rotatable shafts and bars is resiliently mounted on the carrier frame, and wherein the reference represents a reference position.

3. A device that is configured to handle foil for use in a printing process during which transfer portions of a layer of the foil are transferred to a substrate to be printed, the device being intended for arrangement at a printing press having a printing area designed to let such a printing process take place during operation of the printing press, and the device comprising: a foil input unit that is arranged and configured to input at least one foil web to the device; rotatable shafts and bars intended for arrangement upstream and downstream of the printing area, respectively, for directing the at least one foil web to the printing press and retrieving at least one used foil web from the printing press; a controlling arrangement that is configured to control operation of the device; and a web tension feedback unit that is arranged and configured to detect at least one characteristic related to web tension during operation of the device, wherein the web tension feedback unit is in communication with the controlling arrangement; wherein the controlling arrangement is configured to receive information from the web tension feedback unit about the detected characteristic and to process the information by comparing the information to a reference, and to adjust motion and/or positioning of at least one of the rotatable shafts and bars in case the information appears to deviate from the reference.

4. The device of claim 3, wherein the web tension feedback unit comprises at least one of: a visual inspection unit that is arranged and configured to visually inspect an actual pattern of removed transfer portions in a used length of at least one foil web, wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference pattern of removed transfer portions; a pressure detection unit that is arranged and configured to detect pressure exerted by the foil web on at least one area of at least one of the rotatable shafts and bars, and wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference pressure; and a position detection unit that is arranged and configured to detect a position of at least one of the rotatable shafts and bars with respect to a carrier frame, wherein the at least one of the rotatable shafts and bars is resiliently mounted on the carrier frame, and wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference position.

5. The device of claim 3, wherein the foil input unit comprises a rotatable input carrier shaft for carrying at least one reel of foil and reeling out foil of the at least one reel, and an input driving system for driving the input carrier shaft; wherein the input driving system comprises a motor and a coupling unit arranged between the motor and the input carrier shaft; and wherein the coupling unit of the input driving system comprises an electronically controllable device including two rotatably arranged coupling components and a medium situated between surfaces of the coupling components facing each other, the motor of the input driving system being arranged to drive one of the coupling components, and the controlling arrangement being configured to control an extent of slip between the surfaces of the coupling components by varying an extent to which the medium is allowed to couple the surfaces of the coupling components to each other.

6. The device according to claim 5, wherein the electronically controllable device is a magnetic powder clutch including two rotors and magnetic powder particles situated between surfaces of the rotors facing each other, the controlling arrangement being configured to control an extent of slip between the surfaces of the rotors by varying a supply of electrical power to the magnetic powder clutch.

7. The device of claim 5, wherein the input carrier shaft is designed to carry at least two reels of foil and to engage the reels of foil in a slipping fashion, the input carrier shaft being equipped with a mechanism for varying the extent of slip between the respective reels of foil and the input carrier shaft, and the controlling arrangement being configured to control the mechanism.

8. The device of claim 3 further comprising a foil collection unit for collecting used foil; wherein the foil collection unit comprises a rotatable output carrier shaft for carrying at least one reel of foil and reeling in foil to the at least one reel.

9. The device of claim 8, wherein the foil collection unit comprises an output driving system for driving the output carrier shaft; wherein the output driving system comprises a motor and a coupling unit arranged between the motor and the output carrier shaft; and wherein the coupling unit of the output driving system comprises an electronically controllable device including two rotatably arranged coupling components and a medium situated between surfaces of the coupling components facing each other, the motor of the output driving system being arranged to drive one of the coupling components, and the controlling arrangement being configured to control an extent of slip between the surfaces of the coupling components by varying an extent to which the medium is allowed to couple the surfaces of the coupling components to each other.

10. The device of claim 9, wherein the electronically controllable device is a magnetic powder clutch including two rotors and magnetic powder particles situated between surfaces of the rotors facing each other, the controlling arrangement being configured to control an extent of slip between the surfaces of the rotors by varying a supply of electrical power to the magnetic powder clutch.

11. The device of claim 9, wherein the output carrier shaft is designed to carry at least two reels of foil and to engage the reels of foil in a slipping fashion, the output carrier shaft being equipped with a mechanism for varying the extent of slip between the respective reels of foil and the output carrier shaft, and the controlling arrangement being configured to control the mechanism.

12. The device of claim 3 further comprising a foil reuse unit for receiving a used length of foil web from a printing press and feeding the same length of foil web back to the printing press in a longitudinally shifted position so as to allow the printing press to take transfer portions from the length of foil web at positions of the length of foil web which have not been addressed during previous use of the length of foil web in the printing process.

13. The device of claim 3 further comprising at least one direct foil supply bar for supplying a foil web to a printing press, the direct foil supply bar being driven by a motor, and the controlling arrangement being configured to control the motor.

14. The device of claim 13 further comprising a motion detection unit for detecting motion of a cylinder of a printing press for conveying a substrate through the printing area of the printing press; wherein the motion detection unit is in communication with the controlling arrangement; and wherein the controlling arrangement is configured to process information from the motion detection unit and to control the motor for driving the direct foil supply bar for adjusting the speed of a foil web at the position of the direct foil supply bar to the speed of the substrate in the printing area.

15. The device of claim 13, wherein the web tension feedback unit comprises a visual inspection unit that is arranged and configured to visually inspect reference marks on at least one foil web; and wherein the controlling arrangement is configured to receive and process information from the web tension feedback unit about the longitudinal positions of the reference marks and to temporarily adjust motion of the direct foil supply bar in case the longitudinal positions of the reference marks appear to deviate from reference longitudinal positions, during a time that the foil web is allowed to run free in the printing area of the printing press, for adjusting positioning of the foil web in a longitudinal direction during that time.

16. A printing combination comprising: a printing press having cylinders; and the device of claim 3; wherein the device is arranged at a position for supplying at least one foil web to the printing press; and wherein at least the foil input unit of the device is at a position that is at a higher level than cylinders of the printing press.

17. The printing combination of claim 16, wherein the web tension feedback unit comprises at least one of: a visual inspection unit that is arranged and configured to visually inspect an actual pattern of removed transfer portions in a used length of at least one foil web, wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference pattern of removed transfer portions; a pressure detection unit that is arranged and configured to detect pressure exerted by the foil web on at least one area of at least one of the rotatable shafts and bars, and wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference pressure; and a position detection unit that is arranged and configured to detect a position of at least one of the rotatable shafts and bars with respect to a carrier frame, wherein the at least one of the rotatable shafts and bars is resiliently mounted on the carrier frame, and wherein the reference applied by the controlling arrangement while processing information received from the web tension feedback unit represents a reference position.

18. The printing combination of claim 16, wherein the foil input unit comprises a rotatable input carrier shaft for carrying at least one reel of foil and reeling out foil of the at least one reel, and an input driving system for driving the input carrier shaft; wherein the input driving system comprises a motor and a coupling unit arranged between the motor and the input carrier shaft; and wherein the coupling unit of the input driving system comprises an electronically controllable device including two rotatably arranged coupling components and a medium situated between surfaces of the coupling components facing each other, the motor of the input driving system being arranged to drive one of the coupling components, and the controlling arrangement being configured to control an extent of slip between the surfaces of the coupling components by varying an extent to which the medium is allowed to couple the surfaces of the coupling components to each other.

19. The printing combination of claim 16, wherein the device further comprises a foil collection unit for collecting used foil; and wherein the foil collection unit comprises a rotatable output carrier shaft for carrying at least one reel of foil and reeling in foil to the at least one reel.

20. The printing combination of claim 16, wherein the device further comprises: a foil reuse unit for receiving a used length of foil web from a printing press and feeding the same length of foil web back to the printing press in a longitudinally shifted position so as to allow the printing press to take transfer portions from the length of foil web at positions of the length of foil web which have not been addressed during previous use of the length of foil web in the printing process; and at least one direct foil supply bar for supplying a foil web to a printing press, the direct foil supply bar being driven by a motor, and the controlling arrangement being configured to control the motor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments of the present invention will be now described by way of example only with reference to the accompanying drawings in which:

[0031] FIG. 1 shows a foil handling device according to the present invention and a portion of a printing press;

[0032] FIG. 2 shows a perspective view of components of the foil handling device according to the invention, a number of printing cylinders of the printing press, and foil that is used and reused in a printing process;

[0033] FIG. 3 shows a perspective view of a number of printing cylinders as present in a portion of the printing press including a printing area of the printing press, and portions of foil webs running through the portion of the printing press as shown;

[0034] FIG. 4 shows a perspective view of a number of components as present in a first portion of the foil handling device according to the invention, including components of a foil input unit of the foil handling device, components of a foil collection unit of the foil handling device, and portions of foil webs running through the portion of the foil handling device as shown;

[0035] FIG. 5 shows a perspective view of a number of components as present in a second portion of the foil handling device according to the invention, including components of a direct foil drive system of the foil handling device, and portions of foil webs running through the portion of the foil handling device as shown;

[0036] FIG. 6 shows a perspective view of a number of components as present in a third portion of the foil handling device according to the invention, including components of a visual inspection unit of the foil handling device for visually inspecting reference marks on at least one foil web to be supplied to the printing press, and portions of foil webs running through the portion of the foil handling device as shown;

[0037] FIG. 7 shows a perspective view of a number of components as present in a fourth portion of the foil handling device according to the invention, including components of a visual inspection unit of the foil handling device for visually inspecting an actual pattern of removed transfer portions in at least one used foil web, and portions of foil webs running through the portion of the foil handling device as shown;

[0038] FIG. 8 illustrates how the inspected pattern of removed transfer portions can be used in a process of determining whether the web tension is not too high; and

[0039] FIG. 9 is the same as FIG. 4, illustrating an option of having cells on two bars of the foil handling device according to the present invention for measuring forces applied to the respective bars by the foil web.

[0040] The figures are of a diagrammatical nature only and not drawn to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] To facilitate an understanding of the principles and features of the various embodiments of the invention, various illustrative embodiments are explained below. Although exemplary embodiments of the present invention are explained in detail, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the present invention is limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The present invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the exemplary embodiments, specific terminology will be resorted to for the sake of clarity.

[0042] It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. For example, reference to a component is intended also to include composition of a plurality of components. References to a composition containing “a” constituent is intended to include other constituents in addition to the one named.

[0043] Also, in describing the exemplary embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

[0044] Ranges may be expressed herein as from “about” or “approximately” or “substantially” one particular value and/or to “about” or “approximately” or “substantially” another particular value. When such a range is expressed, other exemplary embodiments include from the one particular value and/or to the other particular value.

[0045] Similarly, as used herein, “substantially free” of something, or “substantially pure”, and like characterizations, can include both being “at least substantially free” of something, or “at least substantially pure”, and being “completely free” of something, or “completely pure”.

[0046] By “comprising” or “containing” or “including” is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

[0047] It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Similarly, it is also to be understood that the mention of one or more components in a composition does not preclude the presence of additional components than those expressly identified.

[0048] The materials described as making up the various elements of the present invention are intended to be illustrative and not restrictive. Many suitable materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of the invention. Such other materials not described herein can include, but are not limited to, for example, materials that are developed after the time of the development of the invention.

[0049] As shown and described, the present invention is a device 2 comprising a foil input unit 22 with a foil web 4, a shaft and bar arrangement 13, 14, 15, 16, 17, 21, 27 providing unused foil web 4 to a printing press 1 and retrieving used foil web 4 from the printing press 1, a web tension feedback unit 39, 40, 42 to detect a characteristic related to foil web 4 tension and a controlling arrangement 20 configured to receive the characteristic related to foil web 4 tension from the web tension feedback unit 39, 40, 42, to identify an operable deviation between the characteristic and a reference, and to control the shaft and bar arrangement 13, 14, 15, 16, 17, 21, 27 in response to the identification of the operable deviation. If the deviation between the identified characteristic related to foil web 4 tension and the reference is not great enough to warrant operational changes to the device, then the deviation does not rise to the level of an “operable deviation,” and the controlling arrangement 20 would not be necessarily trigger any adjustment/control to the shaft and bar arrangement 13, 14, 15, 16, 17, 21, 27 beyond its then current operation until such an operable deviation were detected/determined.

[0050] In another exemplary embodiment as shown and described, the device is configured to handle foil for use in a printing process during which transfer portions of a layer of the foil are transferred to a substrate to be printed. The present device is intended for arrangement at a printing press having a printing area designed to let such a printing process take place during operation of the printing press. The device comprises the foil input unit that is arranged and configured to input at least one foil web to the device, the shaft and bar arrangement comprising rotatable shafts and bars for arrangement upstream and downstream of the printing area of the printing press, respectively, for directing the at least one foil web to the printing press and retrieving at least one used foil web from the printing press, the controlling arrangement that is configured to control operation of the device, and the web tension feedback unit that is arranged and configured to detect the characteristics related to web tension during operation of the device, wherein the web tension feedback unit is in communication with the controlling arrangement, and wherein the controlling arrangement is configured to receive information from the web tension feedback unit about the detected characteristic and to process the information by comparing the information to a reference, and to adjust motion and/or positioning of at least one of the rotatable shafts and bars of the shaft and bar arrangement in case the information appears to deviate from the reference to the extent that the shaft and bar arrangement should be adjusted, herein sometimes referred to as an operable deviation.

[0051] In another exemplary embodiment as shown and described, the present invention is a device 2 for handling foil for use in a printing process during which portions of a layer of the foil are transferred to a substrate comprises a foil input unit 22 for inputting at least one foil web 4, 4a, 4b to the device 2, a number of rotatable shafts 21, 27 and bars 13, 14, 15, 16, 17 for directing the at least one foil web 4, 4a, 4b to the printing press 1 and retrieving at least one used foil web 4, 4a, 4b from the printing press 1, an arrangement 20 for controlling operation of the device 2, and a web tension feedback unit 39, 40, 42 for detecting at least one characteristic related to an actual web tension during operation of the device 2 so as to realize web tension control by adjusting motion and/or positioning of at least one of the rotatable shafts 21, 27 and bars 13, 14, 15, 16, 17 in case the characteristic appears to deviate from a reference related to a set web tension.

[0052] FIG. 1 illustrates a combination of a printing press 1 and a device 2 according to the present invention, which serves for handling foil for use in a printing process to be performed in a printing area 3 of the printing press 1. In the shown example, the foil is provided in the form of at least one foil web 4. In particular, the foil comprises two layers, namely a transfer layer such as a metal layer, and a carrier layer. It is intended to have a transfer of portions of the transfer layer from the carrier layer to a substrate (not shown in FIG. 1) such as a sheet of paper or a web of paper in the printing press 1, so that shiny portions are obtained on this substrate. The transfer may be realized in a way known per se, for example, by applying glue to the substrate to be printed and pressing the foil against the substrate, in such a way that the transfer layer of the foil contacts the substrate and is removed from the carrier layer at the areas where the glue is present.

[0053] With respect to the printing press 1, it is noted that this may be many types of printing press 1 that is capable of processing the foil and making shiny portions on printed matter by using the foil. In the example as shown in FIG. 1, the printing press 1 is a so-called offset press, and comprises a number of printing units, wherein one unit is used as a foil printing unit 5 for adding foil to the substrate to be printed, and wherein other units are used as ink printing units 6 for adding various colors to the substrate. The foil printing unit 5 and the ink printing units 6 may be arranged in many suitable orders, depending on a desired sequence of applying foil to the substrate and printing ink on the substrate. A number of cylinders as present in the foil printing unit 5 of the printing press 1 are diagrammatically depicted in FIG. 1. Generally speaking, the foil handling device 2 is arranged at a position above the foil printing unit 5, so that application of the foil handling device 2 with the printing press 1 does not add to the amount of floor space that is needed for the printing press 1.

[0054] In each of the printing units 5, 6 of the printing press 1, a plate cylinder 7 is arranged, that is a carrier of a printing plate. During a printing process, glue or ink is supplied to the printing plate by means of glue/ink cylinders 8 that are arranged in the printing unit 5, 6 as well. Furthermore, dampening cylinders 9 are arranged in the printing unit 5, 6. Areas of the printing plate that are not having an image to be transferred to the substrate are kept in a humid state, as a result of which the ink cannot settle in these areas. According to the principles of offset printing technology, the image is not transferred directly from the printing plate to the substrate. Instead, an intermediate step is performed, in which a blanket is used for receiving the image from the printing plate and transferring the image to the substrate. In the printing unit 5, 6, the blanket is mounted on a blanket cylinder 10 that is arranged at a position between the plate cylinder 7 and a cylinder 11 for supporting the substrate. This substrate supporting cylinder 11 could be an impression cylinder in case of a sheet fed press or a blanket cylinder in case of a web press.

[0055] As the offset printing process is known per se, this process will not be further explained here. In the context of the present invention, it is important to note that the foil web 4 is intended to be supplied to the printing area 3 of the printing press 1, that is an area between the blanket cylinder 10 and the substrate supporting cylinder 11 as present in the foil printing unit 5, wherein measures are taken to maintain a proper web tension.

[0056] The foil web 4 is normally taken from a reel 12, and the foil handling device 2 according to the present invention is designed to realize a continuous supply of foil to the printing press 1. Furthermore, the foil handling device 2 according to the present invention comprises a number of shafts and bars for directing the at least one foil web 4 to the printing press 1 and retrieving at least one used foil web 4 from the printing press 1. In the shown example, the foil handling device 2 comprises a non-driven input bar 13 that is situated at a foil input side of the printing press 1, two driven direct foil supply bars 14, 15 that are also situated at the foil input side of the printing press 1, and two non-driven output bars 16, 17 that are situated at a foil output side of the printing press 1. The foil handling device 2 is suitable for handling one or more foil webs 4, whatever the case may be. In the example as shown, the foil handling device 2 is suitable for handling one or two foil webs 4, and in view thereof, is equipped with two direct foil supply bars 14, 15, wherein only one direct foil supply bar 14, 15 is driven in a case of one foil web 4 being used, and wherein both direct foil supply bars 14, 15 are driven in a case of two foil webs 4 being used.

[0057] The foil handling device 2 is equipped with a unit 18 that is arranged and configured to receive a used length of foil web 4 from the printing press 1, and to feed the length of foil web 4 back to the printing press 1, while changing a mutual position of the length of foil web 4 and the printing press 1. In view thereof, the unit 18 is referred to as foil reuse unit 18. It is noted that further details of the foil reuse unit 18 and an explanation of the way in which this unit 18 is operated will be given later, with reference to FIG. 2.

[0058] In order to achieve excellent printing results, it is important that the speed of the foil web 4 corresponds to the speed of the substrate in the printing press 1. In view of this, the foil handling device 2 is equipped with an encoder unit 19 for detecting the speed of the substrate by detecting the rotational speed of the substrate supporting cylinder 11 of the printing press 1, as can best be seen in FIG. 3. Also, the foil handling device 2 is equipped with a suitable controlling arrangement 20 for controlling operation of the device 2, which is only diagrammatically depicted in FIG. 1 as a block. Among other things, the controlling arrangement 20 is configured to process information provided by the encoder unit 19 during operation, and to control the way in which one of the direct foil supply bars 14, 15 is driven or both of the direct foil supply bars 14, 15 are driven, so as to continually adjust the speed of a foil web 4 at the position of the relevant foil supply bar 14, 15 in order to exactly realize an intended speed of the foil web 4 in the printing area 3, that corresponds to an actual speed of the substrate to be printed.

[0059] A perspective view of components of the foil handling device 2, a number of cylinders 7, 8, 9, 10, 11 of the foil printing unit 5 of the printing press 1, and foil that is used and reused in a printing process are shown in FIG. 2. In the shown example, two foil webs 4a, 4b are taken from two respective reels 12a, 12b. For the purpose of handling the two foil webs 4a, 4b, both direct foil supply bars 14, 15 are driven to supply the respective foil webs 4a, 4b to the printing area 3. Both reels 12a, 12b are supported on a rotatable input carrier shaft 21 that is part of a foil input unit 22 of the foil handling device 2, which foil input unit 22 furthermore comprises an input driving system for driving the input carrier shaft 21. In the shown example, the input driving system comprises a servo motor 23 and a magnetic powder clutch 24 for coupling the motor 23 to the input carrier shaft 21. Both the servo motor 23 and the magnetic powder clutch 24 are electronically controlled by the controlling arrangement 20, so that it is possible to accurately set a speed at which the respective foil webs 4a, 4b run from the foil input unit 22. It is noted that the magnetic powder clutch 24 is one example of a device for controlling slip between rotatable parts that may be used in the foil handling device 2.

[0060] In general, a magnetic powder clutch is an electronically controllable device that is suitable to be used for varying an amount of slip between two rotatable parts coupled through the magnetic powder clutch, which are the input carrier shaft 21 and an output shaft of the servo motor 23 in the shown example. To that end, a magnetic powder clutch comprises two rotors and magnetic powder particles situated between surfaces of the rotors facing each other. When a magnetic field is applied to the particles, the particles are made to form chains between the rotors. The strength of the chains depends on the strength of the magnetic field, and for that reason, it is possible to accurately control friction prevailing inside a magnetic powder clutch by controlling a supply of electrical power to the magnetic powder clutch.

[0061] The foil handling device 2 does not only comprise a foil input unit 22, but also a foil collection unit 25. The latter serves for receiving a portion of each of the foil webs 4a, 4b that is no longer destined to be used. In the shown example, the foil collection unit 25 is designed to wind the portion of each of the foil webs 4a, 4b as mentioned on a reel 26a, 26b that is part of the foil collection unit 25, which does not alter the fact that other possibilities for processing the used portion of a foil web 4a, 4b are feasible within the framework of the invention. Furthermore, in the shown example, the foil collection unit 25 resembles the foil input unit 22 in a constructional sense, comprising an output carrier shaft 27 for supporting the reels 26a, 26b, a servo motor 28 for driving the output carrier shaft 27, and a magnetic powder clutch 29 for coupling the motor 28 to the output carrier shaft 27. In this configuration, it is possible to have accurate control of the motion of the output carrier shaft 27, in a similar manner as is the case with the input carrier shaft 21. It is noted that details of both the foil input unit 22 and the foil collection unit 25 can best be seen in FIG. 4.

[0062] In a manner that is known per se, the input carrier shaft 21 is designed to allow for a slipping arrangement of the reel(s) 12a, 12b on the shaft. Likewise, the output carrier shaft 27 is designed to allow for a slipping arrangement of the reel(s) 26a, 26b on the shaft. In particular, both the input carrier shaft 21 and the output carrier shaft 27 may be tension shafts, i.e. shafts having segments of variable diameter. In case the input carrier shaft 21 is used to support two reels 12a, 12b, the fact that the rotational speed of each of the reels 12a, 12b does not necessarily need to be the same but can be controlled independently allows for compensation of (slight) diameter differences between the respective reels 12a, 12b. The foil handling device 2 may be equipped with many suitable systems for measuring one or more parameters relating to reel size, the controlling arrangement 20 being configured to process the outcome of measurements performed by such system and to control a mechanism for varying the extent of slip between the respective reels 12a, 12b and the input carrier shaft 21 so as to realize proper winding processes at both reels 12a, 12b. Likewise, in case the output carrier shaft 27 is used to support two reels 26a, 26b, the fact that the rotational speed of each of the reels 26a, 26b does not necessarily need to be the same but can be controlled independently allows for compensation of (slight) diameter differences between the respective reels 26a, 26b. The foil handling device 2 may be equipped with many suitable systems for measuring one or more parameters relating to reel size, the controlling arrangement 20 being configured to process the outcome of measurements performed by such system and to control a mechanism for varying the extent of slip between the respective reels 26a, 26b and the output carrier shaft 27 so as to realize proper winding processes at both reels 26a, 26b.

[0063] As mentioned in the foregoing, the foil handling device 2 comprises two driven direct foil supply bars 14, 15 that are situated at the foil input side of the printing press 1, and that are controlled by means of the controlling arrangement 20 on the basis of information provided by the encoder unit 19 during operation, so as to have continuous adjustment of the speed of the foil webs 4a, 4b to the speed of the substrate in the printing area 3 by continuous adjustment of the rotational speed of the direct foil supply bars 14, 15 to the rotational speed of the substrate supporting cylinder 11. In the process, use is made of the fact that in each rotation of the substrate supporting cylinder 11, there is a period in which adjustment of the speed of the foil webs 4a, 4b can be initiated, namely a period in which the foil webs 4a, 4b are allowed to run free in the printing area 3. The fact is that both the blanket cylinder 10 and the substrate supporting cylinder 11 are provided with a gap 30, 31, particularly a break in their circumference, and that during a period of each rotation of the cylinders 10, 11, the gaps 30, 31 of the cylinders 10, 11 are in a position of facing each other. As is known per se, the gaps 30, 31 of the respective cylinders 10, 11 may have a function in accommodating gripping or clamping elements. For example, in the blanket cylinder 10, elements for holding the blanket to the cylinder 10 may be present in the gap 30, and in the substrate supporting cylinder 11, elements for gripping the substrate to be printed and carrying the substrate through the printing area 3 may be present in the gap 31. Each of the direct foil supply bars 14, 15 is driven by means of a servo motor 32, 33 that is controlled by the controlling arrangement 20 of the foil handling device 2 in such a way as to realize a speed of the foil webs 4a, 4b that is accurately adjusted to the speed of the substrate in the printing area 3, wherein corrections in the first speed are made during the period that the gaps 30, 31 of the respective cylinders 10, 11 as present in the printing area 3 are facing each other, that period occurs during each rotation of the cylinders 10, 11, and that period allows for relative movement of the foil webs 4a, 4b with respect to the cylinders 10, 11 in the nip between the cylinders 10, 11. Details of a direct foil drive system 34 comprising the direct foil supply bars 14, 15 and the servo motors 32, 33 for driving the bars 14, 15 can best be seen in FIG. 5.

[0064] Furthermore, as already mentioned, in the shown example, the foil handling device 2 is equipped with a foil reuse unit 18. In FIG. 2, details of an exemplary embodiment of the foil reuse unit 18 are clearly shown. In this embodiment, the foil reuse unit 18 comprises two adjustable angle bar arrangements 35, 36, and two frame portions 37, 38, wherein each of the angle bar arrangements 35, 36 is arranged in another of the frame portions 37, 38, and wherein a level of each of the frame portions 37, 38 in the foil handling device 2 is adjustable. As can be seen in FIG. 2, in the shown example of an application of two foil webs 4a, 4b, the foil reuse unit 18 is used for feeding each of the foil webs 4a, 4b an additional, second time to the printing area 3, wherein each of the foil webs 4a, 4b runs through another one of the frame portions 37, 38 of the foil reuse unit 18. The positioning of the foil webs 4a, 4b as necessary for realizing the second input of the foil webs 4a, 4b to the printing area 3 is accurately controlled, both in the longitudinal direction and the transverse direction, by controlling the level of the frame portions 37, 38 and the positions of the angle bar arrangements 35, 36 in the frame portions 37, 38. To this end, the controlling arrangement 20 of the foil handling device 2 may be configured to process information about the extent to which the foil webs 4a, 4b need to be displaced in both directions as mentioned, and to set the frame portions 37, 38 and the angle bar arrangements 35, 36 in the frame portions 37, 38 at the positions that are correct for realizing an appropriate displacement of the foil webs 4a, 4b with respect to the original input of the foil webs 4a, 4b to the printing area 3. On the basis of the displacement of the foil webs 4a, 4b in the transverse direction, it is realized that other portions of the substrate can be covered by the foil webs 4a, 4b, that have a significantly smaller width than the substrate in the shown example. On the basis of the displacement of the foil webs 4a, 4b in the longitudinal direction, it is realized that another portion of the foil webs 4a, 4b than the portion where the transfer layer is no longer present is put in contact with the substrate at positions where new transfers of material from the foil to the substrate need to take place. When the foil webs 4a, 4b have moved through the printing press 1 two times, the foil webs 4a, 4b move from the printing press 1 to the foil collection unit 25.

[0065] It follows from the foregoing that applying the foil reuse unit 18 offers the important advantage of efficient use of the foil. In a situation without a foil reuse unit 18, only one portion of the transfer layer of a foil web 4a, 4b is used in a printing process, whereas in a situation with the foil reuse unit 18, multiple portions of the transfer layer of the same foil web 4a, 4b are used in a printing process.

[0066] The foil handling device 2 is designed to accurately control longitudinal positioning of the foil webs 4a, 4b in the printing area 3, so that it is actually possible to print many patterns as desired on a series of substrates in a reproducible manner. This is especially relevant in case the foil does not simply have a plain appearance, but is provided with a repetitive pattern of symbols, letters, images, etc. The foil handling device 2 is capable of positioning the specific pattern of the foil on substrates in a predetermined way, on the basis of the fact that the foil handling device 2 is equipped with a visual inspection unit 39 for inspecting reference marks on the foil webs 4a, 4b at the foil input side of the printing press 1, as can best be seen in FIG. 6, and the fact that the controlling arrangement 20 of the foil handling device 2 is configured to receive and process information from the visual inspection unit 39 about the longitudinal positions of the reference marks and to realize an appropriate adjustment of the longitudinal position of the foil webs 4a, 4b by means of the direct foil drive system 34 in case the longitudinal positions of the reference marks appear to deviate from reference longitudinal positions. The visual inspection unit 39 may be located at another position in the foil handling device 2 than as shown and described, as long as it is possible for the visual inspection unit 39 to inspect the reference marks on the foil webs 4a, 4b and provide relevant information that may be compared to the reference.

[0067] The visual inspection unit 39 is arranged so as to inspect a portion of the foil webs 4a, 4b running between the direct foil supply bars 14, 15 and the printing press 1. Another position of the visual inspection unit 39 in the foil handling device 2 may also be chosen. The marks to be inspected may be provided on the foil in many suitable ways, and may even be part of the pattern of the foil. In a practical situation, the marks may be of a transparent character, wherein it is possible for the visual inspection unit 39 to comprise photocells for inspecting the marks. On the basis of the fact that during a process of performing an inspection of the foil webs 4a, 4b, the visual inspection unit 39 is situated at a certain position with respect to the printing press 1, particularly the printing area 3 thereof, a distance measured along the foil webs 4a, 4b to the printing area 3 has a given value. Consequently, taking into account an actual web speed, i.e. a longitudinal speed of the foil webs 4a, 4b, it is possible to determine whether reference marks as inspected are at the right longitudinal position or not. The control can be realized so as to rely on image comparison techniques in the process.

[0068] It is also possible to use the visual inspection unit 39 as mentioned in the foregoing for realizing accurate transverse positioning of the foil webs 4a, 4b in the printing area 3. Whenever an inspected transverse position of a reference mark appears to deviate from a predetermined transverse position, the foil input unit 22 and/or the foil reuse unit 18 can be controlled to allow for the necessary adjustment. Also, it is possible to detect obliquity of the foil webs 4a, 4b, namely by making a comparison of longitudinal positions of two reference marks that are supposed to be exactly the same.

[0069] The foil handling device 2 comprises another visual inspection unit 40, as can best be seen in FIG. 7, which is designed to be used in a process of determining on the basis of visual input whether the web tension is at a correct level, especially a process of determining whether the web tension is not too high. The visual inspection unit 40 is especially arranged and configured to inspect an actual pattern of removed transfer portions in a used length of the foil webs 4a, 4b, and is therefore arranged at the foil output side of the printing press 1, optionally at a position for inspecting a portion of the foil webs 4a, 4b moving directly towards the foil collection unit 25. In the shown example, the visual inspection unit 40 is arranged so as to inspect the foil webs 4a, 4b at a position between the output bars 16, 17 and the foil collection unit 25.

[0070] The visual inspection unit 40 may comprise many suitable types of cameras for obtaining an image from the foil webs 4a, 4b, particularly an image that shows the appearance of the foil webs 4a, 4b, particularly the pattern of the removed transfer portions. The controlling arrangement 20 of the foil handling device 2 is provided with information related to what a certain removed transfer portion should look like in a situation of correct web tension, for example, what the dimension of the removed transfer portion in the longitudinal direction should be. The fact is that at a web tension that is too high, a stretched appearance of the removed transfer portions is detected. In FIG. 8, an illustration of this fact is provided. FIG. 8 shows an example of an appearance of a removed transfer portion 41 on a length of foil web 4, according to which the removed transfer portion 41 is circular, as indicated in FIG. 8 by continuous lines. If the web tension is too high, the removed transfer portion 41 has a stretched appearance, that is an elliptical appearance in this example, as indicated in FIG. 8 by dashed lines, and that has a larger dimension in the longitudinal direction. By using image recognition techniques, or by comparing an actual longitudinal dimension to a reference longitudinal dimension, for example, the controlling arrangement 20 is capable of determining whether the web tension is at a correct level, or not. If the appearance of the removed transfer portions 41 indicates that the web tension is too high, the controlling arrangement 20 can act to make appropriate adjustments in the foil handling device 2, especially by adjusting motion and/or positioning of at least one of the input carrier shaft 21, the output carrier shaft 27 and other driven bars 14, 15 of the foil handling device 2.

[0071] Avoiding a situation of the web tension getting too high in the manner as described in the foregoing involves less waste of foil and substrates compared to a conventional way of doing in which printing results are taken as an indication, and involves a possibility to save costs compared to a conventional way of doing in which pressure on a shaft is measured and taken as an indication of the web tension.

[0072] FIG. 9 relates to an option of using another unit 42 for determining whether the web tension is at a correct level, that unit 42 may be used in addition to the visual inspection unit 40 for inspecting an actual pattern of removed transfer portions in a used length of the foil webs 4a, 4b, as is the case in the shown example, or as an alternative of the visual inspection unit 40. The unit 42 is a pressure detection unit 42 that is arranged and configured to detect pressure exerted by the foil web 4 on at least one area of at least one of the rotatable shafts 21, 27 and bars 13, 14, 15, 16, 17 of the foil handling device 2. In the shown example, the pressure detection unit 42 comprises two sets of cells 43 that are suitable to be used for detecting an actual value of a local pressure, one set of cells 43 being arranged on the non-driven input bar 13 that is situated at the foil input side of the printing press 1, and another set of cells 43 being arranged on one of the non-driven output bars 16, 17 that are situated at the foil output side of the printing press 1, particularly the non-driven output bars 16 that is located at a position closest to the printing press 1 and the printing area 3 as seen in the longitudinal direction. Furthermore, in the shown example, each set of cells 43 comprises four cells 43 that are distributed among the circumference of the respective bar 13, 16. For the sake of completeness, it is noted that within the framework of the invention, the number of the cells 43, the distribution of the cells 43 among the rotatable shafts 21, 27 and bars 13, 14, 15, 16, 17 of the foil handling device 2 and the exact positioning of the cells 43 on the rotatable shafts 21, 27 and bars 13, 14, 15, 16, 17 can be chosen freely, wherein a skilled person will have no difficulty in designing a configuration that may be expected to yield useful measuring results, i.e. measuring results that are suitable to be used in a process of determining whether the web tension is at a predetermined value or within a predetermined range.

[0073] In case the pressure detection unit 42 as mentioned in the foregoing is used in the foil handling device 2, it is practical for the controlling arrangement 20 to be configured to receive the information about an actual value of the pressure on a bar 13, 16 from the respective cells 43, and to process that information, particularly by comparing each pressure value to a reference value of the pressure, in order to find if there are deviations from a reference situation involving a web tension as theoretically determined.

[0074] It will be clear to a person skilled in the art that the scope of the present invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the present invention as defined in the attached claims.

[0075] Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise. Thus, the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0076] It is preferred if the user of the combination of the printing press 1 and the foil handling device 2 is allowed to choose which printing unit of the printing press 1 is used as a foil printing unit 5. Therefore, it is preferred if the foil handling device 2 is arranged in a displaceable support.

[0077] It is noted that in the foil handling device 2, the at least one foil web 4 is contacted by components of the foil handling device 2 only at one side, namely the side of the carrier layer, wherein damage to the transfer layer is prevented. Among other things, this is achieved by using the angle bar arrangements 35, 36 in the foil reuse unit 18.

[0078] Numerous characteristics and advantages have been set forth in the foregoing description, together with details of structure and function. While the present invention has been disclosed in several forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions, especially in matters of shape, size, and arrangement of parts, can be made therein without departing from the spirit and scope of the present invention and its equivalents as set forth in the following claims. Therefore, other modifications or embodiments as may be suggested by the teachings herein are particularly reserved as they fall within the breadth and scope of the claims here appended.