Abstract
Method for holding substrates on a flatbed printing system. After positioning the substrates on the substrate support surface, a leak air area not covered by the substrates is covered by positioning a flexible cover device at least over the leak air area, and preferably over the substrates as well. Thereby, air flow through the through-holes is prevented. An under-pressure is then applied to the through-holes, sucking the substrates against the substrate support surface. The flexible cover device is then withdrawn to expose the substrate for printing while the under-pressure is maintained. It was found that despite the additional amount of air passing through the through-holes uncovered by the withdrawal of the flexible cover device, the under-pressure surprisingly remained sufficient to properly hold the substrates for printing. An additional advantage is that the cover device may be applied easily and rapidly over the leak air area and substrates at once.
Claims
1. A printing system assembly, comprising: a flatbed printing system comprising: a substrate support surface with a plurality of through-holes therein for applying an under-pressure to a plurality of substrates positioned in a substrate area for holding the plurality of substrates against the substrate support surface, thereby defining a leak air area with through-holes not covered by the plurality of substrates; an image forming unit arranged to move in a length direction and a width direction of the substrate support surface for providing an image on the plurality of substrates on the substrate support surface; a cover device moveable between: a cover position wherein the cover device is positioned over: the leak air area to substantially block off air flow through the through-holes in the leak air area; and the plurality of substrates to cover entirely or at least a large portion of the plurality of substrates; and a printing position wherein the plurality of substrates is free of the cover device; a suction source for applying an under-pressure to the plurality of substrates and the cover device via the through-holes; wherein the cover device is flexible for at least partially withdrawing the cover device from at least the leak air area into the printing position, and wherein the flexible cover device is dimensioned to fit over the entire substrate support surface.
2. A method of using the printing system assembly according to claim 1, the method comprising the steps of: positioning the plurality of substrates on the substrate area of the substrate support surface, thereby defining the leak air area with through-holes not covered by the plurality of substrates; positioning the flexible cover device substantially over at least the leak air area to substantially block off air flow through the through-holes in the leak air area; followed by applying the under-pressure to the plurality of substrates and the cover device via the through-holes; and consecutively at least partially withdrawing the cover device from at least the leak air area before the image forming unit providing an image on the plurality of substrates.
3. The method according to claim 2, wherein the step of at least partially withdrawing the cover device further comprises at least partially withdrawing the cover device from the leak air area while an under-pressure is applied to the plurality of substrates and the cover device.
4. The method according to claim 3, wherein: the step of applying an under-pressure comprises activating a suction source to apply an under-pressure to the plurality of substrates and the cover device via the through-holes; and the step of at least partially withdrawing the cover device is performed while the suction source applies the under-pressure.
5. The method according to claim 2, wherein the step of positioning the flexible cover device further comprises the flexible cover device covering the plurality of substrates, wherein the flexible cover device conforms to a geometry of the plurality of substrates.
6. The method according to claim 2, wherein the step of positioning the cover device further comprises positioning the cover device over the substantially entire substrate support surface.
7. The method according to claim 2, wherein the printing system comprises a translatable image forming unit, and wherein the step of withdrawing the cover device further comprises withdrawing the cover device outside of a print area containing at the least one substrate, such that the image forming unit is free to translate over the print area for printing an image on the plurality of substrates.
8. The method according to claim 7, wherein the applied under-pressure to the plurality of substrates is maintained while providing the image on the plurality of substrates, and wherein the step of providing an image is followed by removing the under-pressure from the plurality of substrates and the cover device.
9. The printing system assembly according to claim 1, further comprising an applicator device and an actuator for moving the applicator device with respect to the substrate support surface: in a first direction for applying the flexible cover device on the leak air area and the plurality of substrates; and in a second direction for at least partially peeling the flexible cover device from the substrate support surface.
10. The printing system assembly according to claim 9, wherein the applicator device and the image forming unit are mounted on a carriage, wherein the actuator is arranged for moving the carriage in a length as well as in a width direction of the substrate support surface.
11. The printing system assembly according to claim 1, wherein the cover device comprises a flexible sealing blanket for covering and blocking off through-holes in the substrate support surface.
12. The printing system assembly according to claim 1, further comprising a controller configured for: activating the suction source when the substrate support surface is substantially covered by the plurality of substrates and the flexible cover device; controlling the suction source to maintain an under-pressure on the plurality of substrates while the flexible cover device is being withdrawn.
13. The printing system assembly according to claim 12, wherein the controller is configured to at least partially withdraw the cover device from the leak air area while an under-pressure is applied to the plurality of substrates and the cover device.
14. The printing system assembly according to claim 12, wherein the controller is configured to withdraw the cover device outside of a print area containing at the least one substrate, such that the image forming unit is free to translate over the print area for printing an image on the plurality of substrates.
15. The printing system assembly according to claim 12, wherein the controller is configured to maintain the applied under-pressure to the plurality of substrates while providing the image on the plurality of substrates, and wherein the controller is further configured to remove the under-pressure from the plurality of substrates and the cover device after providing an image.
16. A cover device assembly for use in a printing system assembly according to claim 1, comprising: a flexible cover device for blocking off air flow through through-holes in a substrate support surface of a printing system; an applicator device and an actuator for moving the applicator device with respect to the substrate support surface; a controller for controlling the actuator to move the applicator device: in a first direction for applying the flexible cover device over the substrate support surface and any substrates positioned thereon to cover entirely or at least a large portion of the substrates; and in a second direction for at least partially peeling the flexible cover device from the substrate support surface to uncover the substrates before printing.
17. A flexible cover device for use in a printing system assembly according to claim 1, comprising: a sealing blanket dimensioned to cover substantially the entire substrate support surface and flexible for allowing the sealing blanket to be peeled from the substrate support surface while the sealing blanket is held against the substrate support surface by an under-pressure applied via through-holes in the substrate support surface.
18. The printing system assembly according to claim 1, wherein the flexible cover device conforms to a geometry of the plurality of substrates.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying schematical drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
(2) FIG. 1 is a schematic perspective view of a flat bed printing system;
(3) FIG. 2 is a schematic top view of the printing system in FIG. 1 loaded with substrates;
(4) FIG. 3A-F show schematic cross-sectional views of a printing system assembly according to the present invention during various steps of the method according to the present invention;
(5) FIG. 4 shows a schematic cross-sectional views of a further embodiment of a printing system assembly according to the present invention;
(6) FIG. 5 shows a schematic cross-sectional views of a another embodiment of a printing system assembly according to the present invention;
(7) FIG. 6A-C illustrate a flatbed printing system assembly according to the present invention during different steps of the method according to the present invention; and
(8) FIG. 7A-C illustrate different steps of positioning an embodiment of a flexible cover device according to the present invention on a flatbed printing system.
DETAILED DESCRIPTION OF THE DRAWINGS
(9) The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views.
(10) FIG. 1 illustrates a flat bed printing system 10. The printing system 10 comprises a substrate support surface 14 provided with a plurality of through-holes for applying suction to hold a substrate (S in FIG. 2) against the substrate support surface 14. The through-holes are in fluid connection to a suction source (24 in FIG. 3A) for drawing in air through the through-holes. Thereby, a substrate is sucked against the substrate support surface. In this manner the substrate is held securely in is position while an image is deposited on its top surface by means of an image forming unit 18. The image forming unit 18 comprises one or more print heads for applying ink to the substrate's surface. The image forming unit 18 is arranged to move over and parallel to the substrate support surface 18 in the X and Y directions. In order to avoid contact with the substrate, the distance between the image forming unit 18 and the substrate support surface 14 may be set by moving the image forming unit 18 perpendicularly to the substrate support surface 14 in the Z direction. The image forming unit 18 is provided on a carriage translatable in the X direction along a gantry 16 for printing a swatch on the substrate in the X direction. For positioning the image forming unit 18 in the Y direction, the gantry is translatable in the Y-direction, for example over a guide provided in the side legs 12 of the printing system 10. The printing system further comprises a user interface 20 for inputting print job information to the printing system 10. A controller 22 is provided for controlling the printing process in correspondence with the input print job information.
(11) The substrate support surface 14 is generally large, e.g. over 11 m.sup.2 or more, and arranged to simultaneously hold multiple substrates S, as shown in FIG. 2. Thereby, an operator or loading device may position several substrates on the substrate support surface 14 in a single loading step. These substrates S are then printed in a single pass of the gantry in the Y direction, wherein the image forming unit 18 is iteratively moved in the X direction. This allows for high productivity printing. The dimensions, specifically the shape, size, and/or thickness of the substrates S may vary depending on the desired application of the printed substrates S. Generally, multiple substrates S are positioned together on the substrate support surface 14 to cover as much of the substrate support surface 14 as possible. Areas LA of the substrate support surface 14 not covered by a substrate S are generally closed off prior to printing to achieve sufficient suction to draw the substrates S against the substrate support surface 14. The uncovered area LA may be blocked by means of valves disconnecting said areas LA from the suction source or by covering the areas LA with appropriately dimensioned material, such as tape or remaining print media.
(12) FIG. 2 illustrates a top view of the printing system 10 during after the step of loading the substrates S onto the substrate support surface 14. In consequence of variety in size and shapes of the substrates S, the sum of the surface area SA of the substrates S is less than the area of the substrate support surface 14. Thereby, through-holes not positioned in the substrate area SA, indicated with the dashed pattern, are in fluid connection to the ambient air around the printing system 10. The total area LA of formed by these not covered through-holes forms the leak air area LA through which ambient air may leak into the vacuum table of the printing system 10. This negatively affects the under-pressure for holding down the substrates S. The present invention provides a simple and rapid method for providing sufficient under-pressure to the substrates S.
(13) FIGS. 3A to 3F show various steps of the method for holding a substrate on a printing system 10. FIG. 3A shows the printing system 10 in its initial state prior to performing print job. The substrate support surface 14 comprises a plurality of through-holes extending through the substrate support surface 14 into an inner chamber 26 of the printing system 10. The inner chamber 26 connects the through-holes to the suction source 24. The substrate support surface 14 is relatively large for holding a wide range of substrates S, which may be any type of print media S, ranging from paper or cardboard media to door or wall panels. The number of through-holes in the substrate support surface 14 is very large to properly accommodate this wide variety of different substrate types. It will be appreciated that the through-holes may be provided in any pattern, such as a matrix or regular grid. Further, the inner chamber 26 may in an embodiment be divided into sub-chambers which define suction zones which may be independently of one another be connected and disconnected from the suction source 24. Thereby, suction may be easily applied to common or standard media sizes without air leaking into the vacuum chamber 16 via uncovered through-holes.
(14) FIG. 3B illustrates the step of positioning or loading the one or more substrates S onto the substrate support surface 14. The arrangement of the substrates S on the substrate support surface 14 is preferably determined prior to loading the substrates S to achieve optimal coverage of the substrate support surface 14 for a print job. The arrangement may be input by the operator via a user interface or determined by the controller 22 from the print job information. Therein, an individual section of the substrate area SA is defined for each substrate S to be positioned on the substrate support surface 14. After loading, as shown in FIG. 3B, the substrate support surface 14 comprises said section of the substrate area SA covered by substrates S, as well as regions of the leak air area LA not covered by a substrate S. The through-holes in the latter areas LA provide a fluid connection to the suction source 24, such that when the suction source 24 is activated air will be drawn in via the uncovered through-holes. This leaking of air into the inner chamber 26, prevents the suction source 24 from establishing sufficient under-pressure in the inner chamber 26 to properly draw the substrates S against the substrate support surface 14. This is particularly disadvantageous when one or more substrates are relatively rigid and curved or bent, as shown in the right substrate S in FIG. 3B. Air is also drawn into the inner chamber 26 through the volume between the bent substrate S and the substrate support surface 14.
(15) In order to prevent air from leaking into the inner chamber 26, the present invention proposes covering the leak air areas LA as well as the substrate area SA (and therewith the substrates S) with a flexible cover device 30. The cover device 30 which in FIG. 3C is shown as a sealing blanket 30 is formed of a flexible material substantially impermeable to air. In FIG. 3C, the cover device 30 is dimensioned to fit on or cover substantially the full substrate support surface 14. Thus, as the cover device 30 is applied, substantially all through-holes in the substrate support surface 14 will be prevented from drawing in ambient air. The flexibility of the cover device 30 allows it to conform to the shape of the substrate S, thereby effectively forming a seal over and around the substrate S. This is particularly advantageous in the case of the bent substrate on the right in FIG. 3C. The cover device 30 is applied around the curved substrate S such that ambient air is prevented from being sucked into the inner chamber 26 via the volume between the curved substrate S and the substrate support surface 14.
(16) The flexible cover device 30 is preferably formed of a relatively light and/or thin sheet material, making the cover device 30 relatively easy to apply. When a cover device 30 with an area at least equal to that of the substrate support surface 14 is used, the step of positioning the flexible cover device 30 may be performed even more rapidly, as the cover device 30 may applied in a single motion without regard to the exact shapes or positions of the leak air area LA and the substrate area SA. The method according to the present invention is thus much more time-efficient than the prior art method wherein an operator tapes over all leak individual sections of the air area LA.
(17) FIG. 3D shows the step of activating the suction source 24 with the cover device present on the printing system 10. The suction system 24 draws all air trapped below the cover device without substantially drawing in ambient air. As the cover device 30 (in combination with the substrates S) seals off substantially all through-holes in the substrate support surface 14, the desired under-pressure in the inner chamber 26 is achieved rapidly. Further, a relatively low power suction source 24 may be applied reducing the costs of the printing system 10. The under-pressure at the through-holes induced a pressure force P on the substrates S, drawing these against the substrate support surface 14. As shown in FIG. 3D, the under-pressure is sufficient to draw the curved substrate S flat against the substrate support surface 14 as the cover device 30 forms a circumferential seal around it. Alternatively, the curved substrate S may be actively pressed down against the substrate support surface 14. In this manner, the desired under-pressure for securely holding the substrates S on the printing system 10 is achieved easily and rapidly.
(18) FIG. 3E illustrates the steps of partially withdrawing the cover device 30 from the substrate support surface 14. The withdrawal or removal is performed while the under-pressure is applied to the substrates S and the cover device 30. The suction source 24 is activated. In consequence both the substrates S and the cover device 30 are held or fixed onto the substrate support surface 14. The cover device 30 is initially lifted at a first section 30E, shown as the free end 30E of the cover device 30. This first section 30E is preferably peeled from the substrate support surface 14 as this requires little effort or time despite the under-pressure force P acting on the cover device 30. Peeling in FIG. 3E is illustrated as gradually lifting an increasing section of the cover device 30, starting with the first section 30E, from the substrate support surface 14.
(19) FIG. 3E further illustrates that, during the withdrawal of the cover device 30, ambient air is able to leak into the inner chamber 24 via uncovered regions of the leak air area, shown as air flow A. The inventors found surprisingly that despite the air flow A leaking into the inner chamber 26, the under-pressure remains sufficient to secure the substrates S against the substrate support surface 14 in a manner suitable for printing. It was found that sealing the leak air area was required for initially establishing the under-pressure, but is not required for maintaining the under-pressure after the substrates S have been drawn against the substrate support surface 14.
(20) The cover device 30 is preferably folded back over itself such that the substrates S are free of the cover device 30, as shown in FIG. 3E. In FIG. 3E the cover device 30 has been peeled off in the Y direction to uncover the one or more substrates S on the substrate support surface 14. A second section 30R, shown as the remaining section 30R in FIG. 3F remains on a section of the leak air area LA without covering any substrate S. The cover device 30 in FIG. 3F is thus positioned in a printing position, which allows the image forming unit 18 to deposit an image on all the substrates S on the substrate support surface 14 without interference by the cover device 30. The second section 30R reduces the amount of ambient air flow A into the inner chamber 30. As explained above, the under-pressure or the pressure force P despite the ambient air flow A surprisingly is sufficient for fixing the substrates S flatly on the printing system 10 for printing thereon by the image forming unit 18. Upon completion of the print job, the suction source 24 may be de-activated, the substrates S and the second section 30R of the cover device 30 removed from the substrate support surface 14 to allow for the loading of new substrates S for a further print job. Thereby, the present invention provides a fast, cheap, and simple method of positioning substrates S on a flat bed printing system 10. The present invention is particularly advantageous for packaging material such as, carton or cardboard, as these materials tend to curve or bend. Utilizing the cover device 30 in the above presented manner allows for loading of such material onto the printing system 10 without additional measures for removing the curling or bending.
(21) FIG. 4 shows a further embodiment of the printing system assembly 101 according to the present invention. The printing system 110 is preferably similar to that discussed for FIGS. 1 to 3F and will not be discussed again in detail. The cover device assembly 140 in FIG. 4 comprises the flexible cover device 130 according to the present invention and an applicator device 132 for positioning the flexible cover device 130 over the leak air area LA. The cover device assembly 140 further comprises an actuator for moving the applicator device 132 over the substrate support surface 114. A supply unit 134 in the form of a supply roll 134 is provided for supplying or feeding the flexible cover device 130 onto the substrate support surface 114. It will be appreciated that other forms of supply units 134, such as storage containers or folding units may be applied.
(22) The cover device 130 in FIG. 4 is attached at one end to a holding element 136 positioned adjacent the substrate support surface 114. There from a cover section 130A (the bottom section 130A in FIG. 4) extends at least partially over the substrate support surface 114 for covering and/or blocking off through-holes in the leak air area LA not covered by the substrate S. The applicator device 132 in FIG. 4 is shown as a applicator roller 132. The applicator device 132 and the cover device 130 are preferably table-wide devices 130, 132. The width of the applicator device 132 and the cover device 130 are then at least similar to the width of the substrate support surface 114, measured in a direction X perpendicular to the transport direction Y of the applicator device 132.
(23) The actuator, e.g. an electric linear drive motor or pneumatic cylinder, is arranged to move the applicator device 132 in a transport direction Y over the substrate support surface 114. The applicator device 132 is moveable from a storage position positioned outside or away from the substrate support surface 114 to a cover position positioned over the substrate support surface 114. In the storage position, the substrate support surface 114 is free of the cover device 130 to allow for loading of a new batch of substrates S onto the substrate support surface 114. In the cover position, the cover device 130 covers the leak air area LA not covered by the substrate S. During the step of positioning the cover device 130, the actuator moves the applicator device 132 in the transport direction Y to cover the substrate support surface 114, specifically the leak air area LA, with the cover device 130. The cover device 130 extends from the holding element 136 around the applicator device 132 to the supply unit 134. The cover section 130A between the holding element 136 and the applicator device 132 is in contact with the substrate support surface 114 for blocking off through-holes. A supply section 130B extends between the supply unit 134 and the applicator device 132 over the cover section 130A. The cover device 130 in FIG. 4 thus comprises a U-shaped cross-section curving around the applicator device 132.
(24) As the applicator device 132 moves in the transport direction Y away from the holding element 136 and/or the supply unit 134. The cover device 130 is thereby unwound from the supply unit 134 at roughly twice the speed or rate with which the applicator device 132 moves over the substrate support surface 114. The supply roll 134 is FIG. 4 is preferably pre-tensioned by means of e.g. a spring system, such that when the applicator device 132 moves towards the supply roll 134, the cover device 130 is wound onto the supply roll 134. The pre-tension further aids in spacing the cover section 130A and the supply 130B apart from one another to reduce friction. As such, the cover device may 130 be unwound from the supply unit 134 to cover substantially the entire substrate support surface 114 and any substrate S provided on it.
(25) The embodiment in FIG. 4 is particularly advantageous for unattended printing, especially when combined with a loading device for loading and positioning the substrates S from a substrate supply onto the substrate support surface 114. The controller 22 is arranged to control the actuator to move the applicator device 132 based on the print job. No operator interference is required. In a basic embodiment, the controller 22 is configured to move the applicator device 132 from one side of the substrate support surface 114 before applying the under-pressure and then back when the under-pressure has been applied. In a more advanced embodiment, the controller 22 determines the printing position of the applicator device 132 from the substrate area SA and the leak air area LA. Therein the substrates S are free of the cover device 130 but a region of the substrate surface support surface 114 remains covered by a second section 30R of the cover device 130. The printing position of the applicator device 132 in one embodiment defines the region wherein the gantry 16 moves over the substrates S for printing. Seen in the Y direction, the cover device assembly 130 is then positioned on a side of the gantry wherein no substrates S are present. The gantry 16 is free to move in the region not covered by the cover device 132 without the risk of the two colliding. The controller 22 may further control the activation and de-activation of the suction source 24, respectively after the step of positioning the cover device 130 and after the completion of the printing step. It will be appreciated that the cover device assembly 140 may be applied to a wide variety of different printing systems 110. In one embodiment, the cover device assembly 140 may comprise multiple cover device units each provided with a supply unit and a flexible cover device and provided parallel to one another. Dependent on the width of the printing system 110, the number of cover device units may be adjusted to achieve the desired width. As such various widths may be accommodated while producing one or only a few identical cover device units.
(26) FIG. 5 shows a further embodiment of the printing system 210 according to the present invention. The applicator device 232 and the image forming unit 218 are provided together on the carriage. By moving the gantry 16 in the Y direction, the applicator device 232 applies or peels away the cover device 230. No additional actuator is then required for moving the applicator device 232. The applicator device 232 in FIG. 5 comprises a holding element 232 for releasably holding the end 230E of the cover device 230. The holding device 232 may be e.g. a suction device or a clamping unit. After loading the substrates S, the applicator devices 232 engages the end 230E and by moving the gantry 16 in the Y direction, the cover device 230 is pulled over the substrate support surface 214. For withdrawing, the gantry 16 is moved in the opposite direction thereby peeling the cover device 230 from the substrate S. Prior to printing the applicator device 232 releases the cover device 230. It will be appreciated that the applicator device 232 in this embodiment may also be configured as the applicator device 132 in FIG. 4.
(27) FIG. 6A-C illustrate the steps of an embodiment of the method according to the present invention. The flatbed printing system assembly 1 is shown in top view in FIG. 6A. In FIG. 6A, the substrates S are positioned on a substrate support surface of the printing system 10. The substrate area SA is the collective or total area of the substrate support surface covered by the one or more substrates S. The leak air area LA comprises the through-holes not covered by a substrate S. The leak air area LA is thus the remainder of the substrate support surface not occupied by the substrate area SA. As such, the step of positioning the substrates S divides the substrate support surface into a substrate area SA wherein a substrate S is positioned over through-holes in said substrate area SA and into a leak air area LA in which leak air area LA through-holes are uncovered (i.e. no substrate S is positioned over through-holes in the leak air area LA).
(28) After positioning the substrates S on the printing system 10, the flexible cover device 30 is applied to cover substantially the entire substrate support surface of the printing system 10, as shown in FIG. 6B. Preferably, the cover device is drawn over the substrate support surface in a first direction D1 to at least cover any through-holes not covered by a substrate S. Thereby, the cover device 30 covers at least the leak air area LA. In FIG. 6B, the cover device 30 further covers one or more substrates S. It will be appreciated that the cover device 30 need not cover all substrates S, for example when table-wide substrate S is positioned along an edge of the substrate support surface. It is however advantageous to cover a substrate S with the cover device 30 as it ensures the substrate will be sucked against the substrate support surface, which ensures bent or curved substrates S are properly held against the substrate support surface.
(29) The next step, an under-pressure is applied to both the substrates S and the cover device 30. The flexible cover device 30 forms a seal over the substrate support surface, preventing air from leaking in. Thereby, the substrates S are properly sucked against the substrate support surface.
(30) The following step, the flexible cover device is withdrawn to uncover the substrates S for printing. To that end, the cover device 30 is positioned outside a print area PA, in which the substrates S are positioned. The cover device 30 is positioned such that an image forming unit is able to move freely through the printing area PA to print an image on the substrates S. The print area PA thus includes at least the substrate area SA, but optionally further comprises one or more regions of the leak air area, which regions are positioned in between adjacent substrates S. The cover device 30 is withdrawn outside of the print area PA to a cover area CA, wherein no substrates S are present. When positioned in the cover area CA, the cover device 30 does not impede the movement of the image forming unit through the print area. The cover area CA is preferably part of or positioned in the leak air area LA.
(31) In a consequent step, the image forming unit is moved through the print area PA to print an image on the one or more substrates S.
(32) FIGS. 7A-C illustrate different steps of applying a preferred embodiment of a cover device according to the present invention. FIG. 7A illustrates a flatbed printing system 310 as part of assembly 301, whereupon two substrates S are loaded. The cover device 330 comprises a plurality of cover device elements 330A-C, which together are arranged for sealing the through-holes in the leak air area LA of the substrate support surface. In FIG. 7A, a first cover device element 330A has been positioned on the substrate support surface. The first cover device element 330A comprises one or more windows 330W or openings, preferably dimensioned in correspondence to commonly used substrate sizes. The first cover device element 330A in FIG. 7A covers at least the outer edges of the substrate support surface. The substrates S are preferably positioned relative or central to the windows 330W in the first device element 330A. The substrates S in FIG. 7A are smaller than the windows 330W, so that a portion of the through-holes remains uncovered.
(33) In FIG. 7B, a second cover device element 330B is positioned partially over each of the windows 330W of the first cover device section 330A. The cover device 330 comprises a first cover device element 330A with therein at least a first window 330W and a second cover device element 330B comprising a second window 330W with dimensions smaller than those of the first window 330W. The second cover device element 330B has dimensions smaller than those of the first cover device element 330A and is dimensioned to fit over and cover at least the edges of the first window 330A. When positioning the second cover device element 330B over the first 330A, the second window 330W is then positioned inside the first window 330W, when seen from above. Thereby, the remaining free area of the substrate support surface can be easily reduced. This is illustrated on the right hand side of FIG. 7B, wherein the window 330W of the second cover device element 330B falls over the substrate S on the right. Thereby, the leak air area around the substrate S may be quickly and easily covered.
(34) The circular substrate on the left side of FIG. 7B is still surrounded by uncovered through-holes. To cover these a third cover device element 330C is applied, which is arranged to cover at least the edges of the second window 330W of the second cover device element 330B, such that a third window 330W, with dimensions smaller than those of the second window 330W, is positioned inside the second window 330W, when seen in a top view as in FIG. 7C. The cover device elements 330A-C allow for easy application of the cover device 330. It will be appreciated that in another embodiment the cover device elements may be configured as parallel cover device strips.
(35) Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. In particular, features presented and described in separate dependent claims may be applied in combination and any advantageous combination of such claims are herewith disclosed.
(36) Further, it is contemplated that structural elements may be generated by application of three-dimensional (3D) printing techniques. Therefore, any reference to a structural element is intended to encompass any computer executable instructions that instruct a computer to generate such a structural element by three-dimensional printing techniques or similar computer controlled manufacturing techniques. Furthermore, such a reference to a structural element encompasses a computer readable medium carrying such computer executable instructions.
(37) Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly.
(38) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
