DIGITAL FLATBED CUTTERS

Abstract

A digital flatbed cutter is described. The cutter includes a flatbed on which a printed workpiece can be positioned. A head unit is movable laterally along an x-axis direction and a perpendicular y-axis direction in a parallel plane above the flatbed. The head unit includes a cutter head and a printer head. The printer head includes at least one printhead for overprinting at least part of the printed workpiece with a UV-curable ink or other coating material to provide a raised printing finish, for example. The printer head also include a UV exposure unit configured to expose the applied UV-curable ink or coating material to UV light to cure it.

Claims

1. A digital flatbed cutter comprising: a flatbed on which a printed workpiece can be positioned; a head unit that is movable laterally along an x-axis direction and a perpendicular y-axis direction in a parallel plane above the flatbed; a cutter head mounted to the head unit and including a knife or blade configured to cut the workpiece, the knife or blade being movable along a z-axis direction that is normal to the plane and perpendicular to the x- and y-axes; a printer head mounted to the head unit and including at least one printhead configured to apply a UV-curable ink or coating material to the workpiece; and a control unit configured to control the movement of the head unit using a digital file with cutting information which specifies where the workpiece should be cut by the knife or blade of the cutter head, and overprinting information which specifies where the workpiece should be overprinted with UV-curable ink or coating material by the printhead of the printer head; wherein the printer head further comprises a UV exposure unit configured to expose the applied UV-curable ink or coating material to UV light to cure it.

2. The digital flatbed cutter of claim 1, wherein each printhead is an inkjet-type printhead.

3. The digital flatbed cutter of claim 1, wherein each printhead is configured to apply a transparent UV-curable ink or coating material to the workpiece.

4. The digital flatbed cutter of claim 1, wherein each printhead is configured to apply a non-transparent UV-curable ink or coating material to the workpiece.

5. The digital flatbed cutter of claim 1, wherein the printer head comprises a first printhead configured to apply a transparent UV-curable ink or coating material to the workpiece and a second printhead configured to apply a non-transparent UV-curable ink or coating material to the workpiece.

6. The digital flatbed cutter of claim 1, wherein the UV exposure unit is positioned adjacent the at least one printhead.

7. The digital flatbed cutter of claim 1, wherein the UV exposure unit is adjustable and configured to vary or control the intensity of the UV light to control the curing of the applied UV-curable ink or coating material.

8. The digital flatbed cutter of claim 1, wherein each printhead is movable along the z-axis direction.

9. The digital flatbed cutter of claim 1, further comprising a transfer material applicator head mounted to the head unit and including an applicator roller configured to apply transfer material to the workpiece.

10. The digital flatbed cutter of claim 9, wherein the applicator roller is movable along the z-axis direction.

11. The digital flatbed cutter of claim 1, wherein the flatbed is a conveyor belt configured to move the workpiece along the x-axis direction.

12. The digital flatbed cutter of claim 1, further comprising a creaser head mounted to the head unit and including a creaser wheel configured to crease the workpiece, the creaser wheel being movable along the z-axis direction.

13. The digital flatbed cutter of claim 1, further comprising a tape applicator head mounted to the head unit and including an applicator roller configured to apply a strip of tape to the workpiece.

14. A method of using a digital flatbed cutter, the digital flatbed cutter comprising: a flatbed; a head unit that is movable laterally along an x-axis direction and a perpendicular y-axis direction in a parallel plane above the flatbed; a cutter head mounted to the head unit and including a knife or blade configured to cut the workpiece, the knife or blade being movable along a z-axis direction that is normal to the plane and perpendicular to the x- and y-axes; and a printer head mounted to the head unit and including: at least one printhead configured to apply a UV-curable ink or coating material to the workpiece, and a UV exposure unit configured to expose the applied UV-curable ink or coating material to UV light to cure it; the method comprising: positioning a printed workpiece on the flatbed; overprinting the printed workpiece with UV-curable ink or coating material; and cutting the workpiece.

15. The method of claim 14, further comprising curing the applied UV-curable ink or coating material.

16. The method of claim 15, wherein the UV exposure unit varies the intensity of the UV light to control the curing of the applied UV-curable ink or coating material.

17. The method of claim 14, wherein the digital flatbed cutter further comprises a transfer material applicator head mounted to the head unit, and the method further comprises using the transfer material applicator head to adhere transfer material to the applied UV-curable ink or coating material to define a matching pattern of transfer material.

18. The method of claim 17, wherein the applied UV-curable ink or coating material is only partially cured before the transfer material is adhered.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0052] FIG. 1 is a schematic front view of a digital flatbed cutter according to the present invention;

[0053] FIG. 2 is a schematic side view of the digital flatbed cutter of FIG. 1;

[0054] FIG. 3 is a visual representation of a first digital file for controlling the digital flatbed cutter according to the present invention;

[0055] FIG. 4 is a top view of a first printed workpiece;

[0056] FIG. 5A is a top view of an overprinted business card produced from the first workpiece using the digital flatbed cutter according to the present invention;

[0057] FIG. 5B is a side view of the business card of FIG. 5A;

[0058] FIG. 6 is a visual representation of a second digital file for controlling the digital flatbed cutter according to the present invention;

[0059] FIG. 7 is a top view of a second printed workpiece;

[0060] FIG. 8A is a top view of an overprinted packaging blank for a container produced from the second workpiece using the digital flatbed cutter according to the present invention;

[0061] FIG. 8B is a side view of the packaging blank of FIG. 8A;

[0062] FIG. 9 is a schematic front view of an alternative head unit for the digital flatbed cutter of FIGS. 1 and 2; and

[0063] FIG. 10 is a schematic representation of a process of overprinting and applying transfer material to a workpiece.

[0064] As shown in FIGS. 1 and 2, a digital flatbed cutter 1 includes a flatbed 2 on which a printed workpiece W can be positioned.

[0065] A head unit 4 is mounted above the flatbed 2. The head unit 4 is mounted on a support rail 6 and can move from side-to-side along the support rail (i.e., along a y-axis direction) by a suitable actuator (not shown). The support rail 6 is mounted on side rails (not shown) and can move backwards and forwards along the side rails (i.e., along an x-axis direction) by one or more suitable actuators (not shown). The actuators are controlled by a control unit (not shown) which can include a suitable processor and a user input device such as a touch display screen or keypad, for example. By controlling the actuators, the head unit 4 can be positioned precisely and can be moved in any direction in a parallel plane above the flatbed 2 defined by the perpendicular x- and y-axes.

[0066] The head unit 4 includes a cutter head 8 with a knife or blade 10 and a creaser head 12 with a creaser wheel 14. The knife or blade 10 is mounted so that it can move along the axis that is normal to the plane (i.e., along the z-axis direction). The knife or blade 10 can be moved by an actuator between a first position-shown in FIGS. 1 and 2where it is spaced apart from the workpiece W and a second position where it is in contact with the workpiece for cutting. The creaser wheel 14 is also mounted so that it can move along an axis that is normal to the plane (i.e., along the z-axis direction). The creaser wheel 14 can be moved by an actuator between a first position-shown in FIGS. 1 and 2where it is spaced apart from the workpiece W and a second position where it is in contact with the workpiece for creasing.

[0067] The head unit 4 also includes a printer head 16 with an inkjet-type printhead 18 configured to apply a high-gloss, transparent, UV-curable ink or coating material, and an UV exposure unit 20. The ink or coating material is suitable for overprinting a base image or design that has already been printed on the workpiece so as to provide a raised printing finish. The printhead 18 is connected to an ink supply with one or more replaceable ink cartridges (not shown). At least the printhead 18 can be movable along the z-axis if it is necessary to position each printhead at an optimum distance from the workpiece surface. This allows different thicknesses of workpiece W to be accommodated, for example.

[0068] Although not shown, the head unit 4 can optionally also include a tape applicator head that can be used to apply one or more strips of tape to the workpiece W.

[0069] The cutter head 8, creaser head 12, printer head 16, and optional tape applicator head are conveniently referred to as tool heads and the knife or blade 10, creaser wheel 14, printhead 18 and the applicator roller of the optional tape applicator head as tools. The operation of the tools-including their movement in the z-axis direction and, in the case of the printer head 16 the selective application of the UV-curable ink or coating material by the printhead 18is controlled by the control unit (not shown). The control unit can position the head unit 4 over the workpiece W so that the appropriate tool head is at the required position. In the case of the cutter head 8, the creaser head 12, and the optional tape applicator head (not shown), the control unit can then move the tool down into contact with the workpiece W, move the head unit 4 with the tool is contact with the workpiece to cut, crease or apply tape, move the tool up and away from the workpiece, and reposition the head unit over the workpiece. This can be repeated multiple times until the respective process is complete, after which the next process is carried out or the processing of the workpiece is finished. If the tool is the applicator roller of the optional tape applicator head, it is rotated about the z-axis so that it is aligned with the direction in which the head unit 4 will be moved over the flatbed 2 (i.e., so that its longitudinal axis is substantially perpendicular to the movement direction of the head unit). In the case of the printer head 16, the control unit can optionally adjust the position of the printhead 18 so that it is at the optimum distance from the workpiece surface. The control unit then moves the head unit 4 in one or more passes over the stationary workpiece W to apply UV-curable ink or coating material to those parts of the workpiece where overprinting is needed. In each pass, the printer head 16 is moved along the y-axis directioni.e., from side-to-side across the flatbed 2. Between each pass, the printer head 16 is moved along the x-axis direction. For example, during the overprinting process, the printer head 16 can be moved along the y-axis direction from a first edge of the workpiece W towards a second, opposite, edge of the workpiece while selectively applying a layer of UV-curable ink or coating material to those parts of the printed workpiece that need to be overprinted. The printer head 16 can then either be moved back to the first edge and moved a pre-determined distance along the x-axis direction, before being moved along the y-axis direction from the first edge towards the second edge, or moved a pre-determined distance along the x-axis direction, before being moved along the y-axis direction from the second edge towards the first edge. This is repeated until the overprinting of the workpiece W is complete. In the first case, the UV-curable ink or coating material is applied only when the printer head 16 is moved from the first edge towards the second edge in each pass. In the second case, the UV-curable ink or coating material is applied both when the printer head 16 is moved from the first edge towards the second edge and when the printer head is moved from the second edge towards the first edge. To reduce the number of passes needed for each overprinting process, the printer head 16 can include two or more printheads 18 arranged side-by-side in the x-axis direction so that more of the workpiece W can be overprinted in each pass. But it will be understood that this can increase the cost of the printer head. Alternatively, the printer head 16 is moved along the x-axis direction in each pass and is moved along the y-axis direction between passes. As described above, two or more overprinting process can be carried out sequentially to obtain contour effects or texturing. The applied UV-curable ink or coating material is cured by the UV exposure unit 20 after it has been applied to the workpiece surface (or to an existing layer of UV-curable ink or coating material). In the case where the UV-curable ink or coating material is only applied when the printer head 16 is moved from the first edge of the workpiece towards the second edge, the UV exposure unit 20 is preferably located on the trailing side of the printhead 18see FIGS. 9 and 10, for example. The printer head 16 can include two or more UV exposure units if required.

[0070] The digital flatbed cutter 1 can include a feed mechanism (not shown) for positioning a workpiece on the flatbed 2. Any suitable feed mechanism can be used, e.g., a vacuum feed that can be integrated into the head unit 4 or the support rail 6 and which can be used to pick up an individual workpiece from a stack and position it on the flatbed 2.

[0071] The flatbed 2 can be a conveyor belt which can be used to support the workpiece W while it is being worked and move the workpiece to a collection tray.

[0072] The movement of the head unit 4 can be controlled by the control unit using a digital file.

[0073] A visual representation of the digital file for business cards is shown in FIG. 3 where cutting information is shown in solid line and overprinting information is shown as an oval-shaped area. In particular, the solid lines indicate where the workpiece W shown in FIG. 4 should be cut by the cutter head 8 to form the outer edges of the business cards, and the oval-shaped areas indicate where the workpiece should be overprinted by the transparent UV-curable ink or coating material to create a raised printing finish. It will be understood that the oval-shaped areas are only provided as a simple example, and that in practice the areas for overprinting can have any suitable shape and will normally be determined by the shape of the printed areas on the workpiece that are intended to be overprinted. The designated areas for overprinting the workpiece can be intricate and complex and are limited only by the print capabilities of the printhead 18 of the printer head 16.

[0074] The workpiece W shown in FIG. 4 is a printed sheet of card stock. The workpiece W has printed areas that are indicated by the cross hatching. The printed areas (i.e., base images or designs) can be pre-printed on the workpiece by any suitable printing process such as inkjet printing or laser printing, for example. The oval-shaped printed areas are intended to be overprinted.

[0075] The workpiece W also includes six printed registration marks M1, M2, . . . , M6.

[0076] The workpiece W shown in FIG. 4 is positioned on the flatbed 2 using the feed mechanism (not shown). A stack of identical printed workpieces can be located at an end of the flatbed 2 and an individual workpiece can be picked from the stack and positioned on the flatbed. The head unit 4 is precisely aligned with the workpiece W. For example, the head unit 4 can include a camera (not shown) and the control unit can use optical recognition of the printed registration marks M1, M2, . . . , M6 to determine the precise position and orientation of the workpiece W on the flatbed 2. Once the head unit 4 has been precisely aligned relative to the workpiece W, the workpiece can be overprinted by the printer head 16 and cut by the cutter head 8 based on the respective information in the digital file. More particularly, the workpiece W can be overprinted by moving the head unit 4 over the workpiece in a series of passes as described above while the printer head 16 is controlled to selectively apply a layer of the UV-curable ink or coating material to the relevant parts of the workpiecei.e., to the oval-shaped printed areas. (It will be understood that the oval-shaped areas of the digital file are in register with the oval-shaped printed areas on the workpiece W so that the oval-shaped printed areas shown in FIG. 4 are overprinted with the UV-curable ink or coating material.) The workpiece W is then cut by the cutter head 8 to produce separate business cards. The overprinting and cutting process are therefore carried out quickly and cost-effectively using the digital flatbed cutter and without the problems that occur when a guillotine is used to cut a stack of overprinted workpieces.

[0077] A single business card C is shown in FIGS. 5A and 5B and includes an area of overprinted UV-curable ink or coating material I that is applied over the oval-shaped printed area as a raised finish. The oval-shaped printed area of the business card C is visible through the UV-curable ink or coating material, which is transparent.

[0078] A visual representation of the digital file for a packaging blank is shown in FIG. 6 where cutting information is shown in solid line, creasing information is shown in dashed line, tape application information is shown in dotted line, and overprinting information is shown as an oval-shaped area. In particular, the solid lines indicate where the workpiece W shown in FIG. 7 should be cut by the cutter head 8, the dashed lines indicate where the workpiece should be creased by the creasing head 14, the dotted lines indicate where a strip of tape of pre-determined width should be applied to the workpiece, and the oval-shaped area indicates where the workpiece should be overprinted by the transparent UV-curable ink or coating material to create a raised printing finish.

[0079] The workpiece W shown in FIG. 7 is a printed sheet of card stock. The workpiece W has printed areas that are indicated by the shading and which will be the outer surfaces of an assembled container. The printed areas (i.e., base image or design) can be pre-printed on the workpiece by any suitable printing process such as inkjet printing or laser printing, for example. The oval-shaped printed area is intended to be overprinted.

[0080] The workpiece W also includes six printed registration marks M1, M2, . . . , M6.

[0081] The workpiece W shown in FIG. 7 is positioned on the flatbed 2 using the feed mechanism (not shown). A stack of identical workpieces can be located at an end of the flatbed 2 and an individual workpiece can be picked from the stack and positioned on the flatbed. The head unit 4 is precisely aligned with the workpiece W. For example, the head unit 4 can include a camera (not shown) and the control unit can use optical recognition of the printed registration marks M1, M2, . . . , M6 to determine the precise position and orientation of the workpiece W on the flatbed 2. Once the head unit 4 has been precisely aligned relative to the workpiece, the workpiece can be overprinted by the printer head 16, cut by the cutter head 8, creased by the creaser head 12, and tape can be applied by the tape applicator head (not shown) based on the respective information in the digital file. The processes can be carried out in any suitable order.

[0082] The workpiece W can be overprinted by moving the head unit 4 over the workpiece in a series of one or more passes as described above while the printer head 16 is controlled to selectively apply a layer of the UV-curable ink or coating material to the relevant part of the workpiece.

[0083] In a tape application process, the head unit 4 can be positioned over a first glue tab GT1, the applicator roller (not shown) can be rotated about the z-axis to be aligned with the x-axis and moved down into contact with the workpiece, the head unit can be moved in the x-axis direction to apply a first tape strip S1 to the first glue tab GT1, the applicator roller can be moved up and away from the workpiece, the head unit can be re-positioned over a second glue tab GT2, the applicator roller can be rotated about the z-axis to be aligned with the y-axis and moved down into contact with the workpiece, the head unit can be moved in the y-axis direction to apply a second tape strip S1 to the second glue tab GT2, and the applicator roller can be moved up and away from the workpiece. (This assumes that the workpiece W has been positioned on the flatbed 2 such that its edges are exactly aligned with the x- and y-axes of the cutter. In practice, the edges of the workpiece W are likely to be mis-aligned with the x- and y-axes of the cutter such that the head unit 4 is moved along directions that are angled slightly with respect to the x-axis direction and the y-axis direction with the applicator roller (not shown) being rotated about the z-axis accordingly.) It will be understood that the applicator roller is not limited to applying tape strips that are aligned with the x-axis direction or the y-axis direction. In practice, the applicator roller can be rotated about the z-axis to be aligned with any direction in which the head unit 4 can be moved. For example, the applicator roller can be used to apply a diagonal tape strip that is not aligned with either the x-axis direction or the y-axis direction. In some arrangements, the applicator roller can be rotated about the z-axis while it is in contact with the workpiece and is applying tape if the movement direction of the head unit 4 changes.

[0084] FIGS. 8A and 8B show a finished packaging blank B for a container with the tape strips S1 and S2 applied to the glue tabs GT1 and GT2. If the tape strips S1, S2 are double-sided tape, the backing layer can be removed to expose the adhesive and the packaging blank can be folded and assembled to form a container. The packaging blank B also includes an area of overprinted UV-curable ink or coating material I that is applied over the oval-shaped printed area as a raised finish.

[0085] FIG. 9 shows part of a different head unit 4 for the digital flatbed cutter 1 that includes a transfer material applicator head 22. The transfer material applicator head 22 is mounted to the head unit 4 next to the printer head 16.

[0086] The transfer material applicator head 22 includes an applicator roller 24 with a longitudinal axis that is aligned with the x-axis direction. The applicator roller 24 can be moved along the axis that is normal to the plane (i.e., along the z-axis direction). The applicator roller 24 can be moved by an actuator between a first position-shown in FIG. 9where it is spaced apart from the workpiece W and a second positionshown in FIG. 10where it brings the transfer material into contact with the applied ink or coating material.

[0087] Transfer material (or foil) is supplied to the applicator head 24 from a roll 26. As shown more clearly in FIG. 10, the transfer material TM is releasable adhered to a backing material BM. Waste material is collected on a waste roll 28.

[0088] FIG. 10 shows an example of a process of applying transfer material to the workpiece W. The arrow indicates the direction of movement of the head unit 4 relative to the stationary workpiece Wi.e., from right to left along the y-axis direction. (Alternatively, the head unit can be moved along the x-axis direction and the longitudinal axis of the applicator roller 24 can be aligned with the y-axis direction.) UV-curable ink or coating material I is only applied to the workpiece W by the printhead 18 when the head unit 4 is moving in this particular direction and the UV exposure unit 20 is therefore positioned on the trailing side of the printhead 18 so that the ink or coating material is exposed to the UV light after it has been applied to the workpiece W. The applied UV-curable ink or coating material I is only partially cured by the UV exposure unit 20 so that it remains slightly tacky. The UV-curable ink or coating material I may be transparent or non-transparent and may optionally be applied from a separate printhead (not shown) of the printer head 16.

[0089] The transfer material applicator head 22 is positioned on the trailing side of the printer head 16. In FIG. 10, the applicator roller 24 is shown in the second position where it is adhering transfer material TM from the roll 26 to the ink or coating material I. The adhered transfer material TM is shown on the trailing side of the applicator roller 24. Backing material BM from the roll 26 together with any non-adhered transfer material TM is gathered on the waste roll 28. Transfer material TM is only adhered to the tacky ink or coating material I to form a pattern of applied transfer material that matches the pattern of the applied ink or coating material. The workpiece W can be overprinted and coated with transfer material to form the desired finish in a series of passes. When transfer material is not being applied, the applicator roller 24 can be raised to the first position.