CORRUGATED SHEET PROCESSING APPARATUS

Abstract

A corrugated sheet processing apparatus (120) is disclosed, comprising feed and guide rollers for selecting, moving and supporting sheets or webs to a corrugator (136) for forming a corrugated sheet; and a control system for controlling the sheet processing equipment (136) or a cutter (148); the sheet processing apparatus (136) further comprising a visual inspection unit (162) for reading printed information markers on at least one printed sheet or web as the printed sheet or web pass through the corrugated sheet processing apparatus (136), or corrugator; and wherein the control system further has a data look-up table whereby the apparatus (120) can identify what products will be produced downstream of the visual inspection unit, and the required settings for the sheet processing equipment or corrugator for those products.

Claims

1. A corrugated sheet processing apparatus comprising: sheet processing equipment comprising a corrugator and at least feed and guide rollers for selecting, moving and supporting sheets or webs to the corrugator for forming a corrugated sheet from which corrugated products can be cut, at least one layer of the corrugated sheet, and thus of the products, being formed from a printed sheet or web; and a control system for controlling the sheet processing equipment; the corrugated sheet processing apparatus further comprising a visual inspection unit arranged for reading printed markers provided on at least one printed sheet or web as the printed sheet or web, and thus the printed markers to be read, pass through the corrugated sheet processing apparatus, or the corrugator thereof; wherein: the printed markers are printed information markers having identifier information thereon; the corrugated sheet is for more than one product order, the products of one order compared to a previous order having differing required details, comprising any one or more of a) differing shapes, b) differing forms or types for at least one of the sheets or webs, c) differing numbers of webs, and d) differing glue types, glue temperatures, glue thickness or glue locations; and the control system further has a data look-up table comprising, for the products to be cut from the corrugated sheet, at least (1) details information associated with the said differing details of the more than one product order, and (2) associated with said details information, said identifier information readable from the printed information markers by the visual inspection unit, whereby the apparatus can identify what products or product orders will need to be produced downstream of the visual inspection unit, and identify in advance required settings for the sheet processing equipment or corrugator for those products or product orders, in response to a read printed information marker, so that the sheet processing equipment or corrugator can be appropriately controlled by the control system to meet the said required details of the products for each of the various product orders.

2. The apparatus of claim 1, wherein each printed information marker is a QR code or bar code and the visual inspection unit includes an appropriate reader therefor.

3. The apparatus of claim 1, wherein the look up table is a reel map.

4. The apparatus of claim 1, wherein each marker is uniquely identified by its printed information whereby its position within a particular order can be ascertained.

5. The apparatus of claim 1, wherein two different product orders are sequentially positioned longitudinally along the length of the corrugated sheet.

6. The apparatus of claim 1, wherein only some of the printed images have an associated unique printed information marker.

7. A method of using the apparatus of claim 1, wherein the sheet or web with the information marker printed thereon is fed past the visual inspection unit, the information on the information marker is read and the information thereon is used by the control system to prepare the apparatus for any required changes to meet the required details of the identified product or product order.

8. A method of using the apparatus of claim 1, wherein the control system is adapted to automate a timing of a change to allow the corrugated sheet formed in the corrugator to change within the material stream so as to alter from one form to another form that matches a requirement set out in the data look-up table for the product to be cut therefrom.

9. The apparatus of claim 1, wherein the sheet processing equipment includes at least one splicing unit.

10. A method of using the apparatus of claim 9, wherein, upon noting a forthcoming requirement change by reference to the look-up table, and when an appropriate different source roll is already loaded into the splicing unit of the sheet processing equipment, the control system and the sheet processing equipment operate to switch out a first source roll and splice in the different source roll, so as to achieve a change in the material input for the corrugator.

11. The method of claim 10, wherein the sheet processing equipment is arranged to operate the switch within the splicing unit within 10 seconds of noting the requirement change.

12. The method of claim 10, wherein the switch may be triggered within a linear distance of travel of the sheet materials of 10 m, such that the switch is done by the time that the read information marker that noted the requirement change has moved further through the apparatus by no more than 10 m.

13. The apparatus of claim 9, wherein the sheet processing equipment comprises a splicing unit for each layer of the corrugated sheet, such that the properties of each layer is independently switchable.

14. A method of using the apparatus of claim 1, wherein the sheet processing equipment can affect a reduction or increase in the number of layers within the corrugate.

15. The apparatus of claim 1, further comprising: downstream processing equipment, the downstream processing equipment comprising at least feed and guide rollers for moving or supporting a corrugated sheet and at least one cutting apparatus for cutting products from the corrugated sheet; wherein: the control system is also for controlling the cutting apparatus.

16. The apparatus of claim 1, wherein the printed information markers are located in a waste portion of the corrugated sheet.

17. The apparatus of claim 1, wherein the corrugated sheet comprises printed images on at least one of its surfaces for appearing on the surfaces of the final products.

18. The apparatus of claim 17, wherein the printed images do not overlap the printed information markers.

19. The apparatus of claim 15, wherein the cutting apparatus includes one or more longitudinal cutting unit or blade for cutting the corrugated sheet lengthways to define a predetermined width for a part thereof and the predetermined width is part of the information retained in the look-up table for each product order.

20. The apparatus of claim 15, wherein the apparatus comprises one or more cross-cut apparatus adapted to cut the corrugated sheet into a predetermined length to form lengths for stacking and the predetermined length is part of the information retained in the look-up table for each product order.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0105] These and other features of the present invention will now be described in greater detail, purely by way of example, with reference to the accompanying drawings in which:

[0106] FIG. 1 schematically shows a prior art rotary screen printing process;

[0107] FIG. 2 schematically shows a sheet processing apparatus in the form of a corrugated cardboard making machine;

[0108] FIG. 3 shows a typical layout of a printed sheet from a screen printing machine such as that of FIG. 1also producible on a digital printer;

[0109] FIG. 4 shows a possible output from a digital printer in which images for three different product runs are being provided;

[0110] FIG. 5 shows a further possible output from a digital printer in which images for four different product runs are being provided;

[0111] FIG. 6 shows an arrangement in which two digital printers are provided, and in which a slightly larger spacing between print jobs is being providedslightly larger than the spacing between images of the same print job;

[0112] FIG. 7 shows another arrangement in which two digital printers are provided in which one of the printers is printing images for a pair of products the total combined width of which (including a trim area between them) exceeds the width of the printer;

[0113] FIG. 8 schematically shows a portion of a sheet processing apparatus wherein the printed sheet media or web is cut into two separate webs, each for separate downstream processing (as herein shown they are cut into stackable sheet products;

[0114] FIG. 9 schematically shows a possible form of reel map for representing a section of a printed sheet mediatwo short product runs are shown in full, and parts of four more product runs are shown at the endstwo at each end (in practice a product run is likely to contain many tens or hundreds of products, rather than the illustrated nine and eight products, respectively, although the present invention does facilitate an efficient production of such short product production runs, if ever desired);

[0115] FIG. 10 schematically shows a possible location for printed information markings on a printed sheetin a waste portion (i.e. a cut-off or trim portion), such as the area surrounding a die-cut product or in the waste area next to glue-tabs;

[0116] FIGS. 11 to 13 show an adaptive reel map being updated to form a corrected reel map, such as may occur when a section of a printed sheet from a roll has a detected print error on it (or a tear)in this instance in ID location 17. The faulty section of the printed sheet may be discarded downstream, or removed and the sheet re-spliced together so that the sheet processing apparatus can still process the roll. For the latter, the reel map is updated to reflect the removal so that the reel map can maintain track of the images actually present on the reel as it passes through the sheet processing apparatus (by following the reel map and checking against data from in-line camerason the production linefor conformance);

[0117] FIG. 14 shows the reel map adapting to a corrugator or sheet processing apparatus stop event, such as a paper break within a product run;

[0118] FIG. 15 shows the reel map adapting to a corrugator or sheet processing apparatus stop event, such as a paper break bridging more than one product run;

[0119] FIG. 16 shows a schematic view of a wet end of a corrugate former;

[0120] FIGS. 17 and 18 are more detailed views of the apparatus of FIG. 16;

[0121] FIG. 19 is a further wet end of a corrugate former showing additional elements thereof; and

[0122] FIG. 20 shows a dry end of a corrugate former where the corrugated sheets are cut from the continuous stream of corrugate formed thereon.

DESCRIPTION

[0123] Referring first of all to FIG. 2 there is illustrated an apparatus 120 from which a product 146 can exit or travel at high speed or high frequency, which product 146 features a printed surface. High speed typically encompasses linear transport speeds of over 50 mpm (metres per minute)the peak feed speed of the webs in the apparatus. These products are cut from a continuous sheet (a corrugated sheet in this embodiment) that is formed therein. This corrugated sheet, also referred to as a printed sheet media, generally has a width of over 600 mm, and most typically a width of more than 1 m, or 1.5 m, or 2 m or 2.4 m.

[0124] The printed sheet media of that embodiment has a printed top sheet or web 126. The printed top sheet can be produced off-line, i.e. at a separate process station, such as in a rotary screen printing machine 108 as shown in FIG. 1. However, for implementing the advantages of the present invention it will typically be digitally printed by a digital printer (or multiple digital printers)so that information markers, or varying images, can be provided.

[0125] The off-line printer will typically print the required product's images 1 12 onto a surface of the web 126, and then a laminating process joins the printed web 126 to a surface of a second sheet 130one that is used to form the product 146s. See FIG. 2. This basic operation, when using screen printers, is a common process in the production of corrugated cardboard products. Adding digitally printed images or information markers, however, is a new development of the present invention.

[0126] The easiest way to add these new images or information markers is with digital printers. They offer greater flexibility in that they allow a wide variety of output images A, B, C, D on a single roll, as can be seen in FIGS. 4, 5, 6 and 7. In particular, the images on a single roll can have a wider variety of widths and lengthsthere is no need to be tied to the size and form of a screen print roller.

[0127] Referring again to FIG. 2, the corrugated cardboard manufacturing apparatus 120 takes four webs 126, 130, 140, 138 and combines them into a corrugated printed sheet media having a single corrugated layer and an uppermost printed web 126. As described above, that top web is unraveled off an output roll 1 18 that has previously been processed by a printing machine 108, such as a digital printer 166 as shown schematically in FIG. 4, 5, 6 or 7, or potentially a rotary screen printer as shown schematically in FIG. 1.

[0128] The three lower webs 130, 140, 138 are also each unraveled off a respective roll 122A, 122B, 122C. These webs are generally unprinted.

[0129] Being ultimately for forming corrugated cardboard, it is generally the case that these four rolls will all be in the form of paper, and usually kraft paper.

[0130] The three lower webs are arranged in the machine 120 such that an uppermost one 130 forms an upper wall of the corrugated cardboard structure, a lowermost one 138 forms a lower wall of the corrugated cardboard structure and a middle web 140 forms the corrugated core 164 of the corrugated cardboard structure. The web 126 from the output roll 1 18 instead just provides an upper facing for the upper wall of the corrugated cardboard structure.

[0131] To laminate or attach that upper facing to the uppermost web 130 of the corrugated cardboard structure, numerous approaches can be taken, but a typical one, as shown, involves spraying glue to an underside of the pre-printed web 126, as it unrolls off the output roll 1 18, using a glue sprayer 128, and then that pre-printed web 126 can be properly laminated or adhered onto the upper surface of the uppermost web 130 as the two webs 126, 130 are fed through a pair of pinch rollers 132.

[0132] That pre-laminated top wall 134 can then be fed down to a corrugator 136, which joins the three lower webs together in a known manner (the middle web 140 and the lowermost web 138 had meanwhile been fed also to the corrugator 136 as well).

[0133] The middle web has an additional process step applied to it before it is joined to the upper laminated web and the lower web: it is additionally passed through a corrugating device 142 which generally uses a fluted roller for folding flutes or corrugations therein.

[0134] The corrugator 136 then combines and glues these layers together, with the resulting corrugated sheet then being pinched together and heated to set the glue by further pinch rollers 144 and possibly blowers 162, thus forming the corrugated cardboard sheet.

[0135] That corrugated cardboard sheet is then further processed as appropriate for a particular customer's requirements, including cutting it to a predetermined length across the width of the web, e.g. using a reciprocal blade cutter 148, so as to form separate sheets or units 146 prior to then stacking those units 146 on a pallet 150. Only the cutting step is shown in this simplified schematic.

[0136] The physical arrangement of the various elements of these corrugated cardboard manufacturing machines can vary considerably over that which is shown schematically in FIG. 2. For example, it is generally the case that the machines 120 involve numerous linearly separated machines, rather than machines in which the rolls are arranged one above the other. Further, the various units, by being linearly arranged, can form a manufacturing line which is generally straight, albeit with vertical variations to accommodate the different layers of the corrugate and web tension maintenance mechanisms. Additional rollers, heaters and processing units (perforators, scorers, cutters, etc.) can also be provided as commonly known in the art.

[0137] A typical manufacturing line of this type can be in excess of 50 m in length.

[0138] In addition to the cross-cut (i.e. a transverse cut of the longitudinal web or sheet) as provided by the blade cutter 148 schematically shown in FIG. 2, longitudinal cuts are likely also to be made to the webs or corrugated sheet prior to stacking. A simplified form of longitudinal cutter is shown schematically in FIG. 8. Such longitudinal cutting equipment can utilised a blade such as a rotary blade cutter 152 for cutting the corrugated cardboard sheet 154 into two (or more, by the provision of further blades) separate lines 156a, 156b. The blades, e.g. where multiple such blades are provided, can also be for removing linear waste portions from the webs or sheet.

[0139] As shown, the rotary blade cutter 152 can be moved sideways across the width of the corrugated cardboard sheet 154 for accommodating different output requirements. This therefore allows the equipment to adapt to accommodate different jobs along the length of the printed sheet media even where those jobs are arranged side by side.

[0140] With the digital printer(s), the relevant web can be printed directly within the machine 120 or off-line, dependent upon the location of the printer. However, pre-printing the webs 126 is generally more practical.

[0141] Referring now specifically to FIG. 4, there can be seen four side-by-side lines of printed images. The images take the form of three separate print runs A, B, C, with the leftmost print run being print run A, the middle two print runs being both print run B, and the rightmost print run being print run C.

[0142] Between the print runs dotted lines 168 are shown. Those dotted lines represent the location of cuts to be performed further downstream on the apparatus. They are not usually printed onto the web. They are shown in the drawings for illustrative purposes only.

[0143] Down one side of the web, there is also shown a solid, continuous line 170. This line often is printed by the printer. It provides a reference line for indexing further down the apparatus. The longitudinal cutting units 152 can be indexed off that solid, continuous line. Additional solid continuous lines might also be provided elsewhere on the web, especially where the web is split (as in FIG. 8) as the second line can provide the same purpose for the second of the lines.

[0144] The solid continuous line 170 may also feature marks for indicating where the transverse cuts are to be performed. Those marks could then be used as index marks for the crosscut blades 148, be that for a single crosscut unit, or multiple separate crosscut units (in which case the second continuous lines mentioned in the preceding paragraph would be beneficially present).

[0145] The four print runs A, B, C in FIG. 4 are printed using a single print bar 166, which extends across the full width W of a substantially continuous web 134. By being a single print bar 166, typically no movements of the print bar relative to the web 134 will be required. Given the lack of availability of very wide format digital printers for high-speed, roll-fed, sheets, it is likely that such a single print bar arrangement will be limited to applications where the web has a maximum width of perhaps 1 m. However, as wider print bars are produced by manufacturers, the width of the web can be widened too. As can be seen the print jobs do not have coincident endsproducts A are shorter than products B and products C are longest of all. This form of printing cannot be achieved with a screen printer as a screen printer is limited to a fixed circumference and thus a fixed print periodicity. For this reason digital printers are preferred to be adopted for offering greater print flexibility and thus better order management, as will be explained further below.

[0146] To accommodate wider webs, multiple print bars can be provided, and the print bar(s) can be mounted on a carriage for being movable relative to the web (or the web may be movable on its rollers for movement relative to the print bar). The relative movement allows jobs with different waste margins to be accommodated, and potentially the printing of products with a wider width than the length of the print bar (where the printed part does not exceed the printer's length). This is further explained in relation to FIG. 7, in which two print bars are provided, each mounted on a movable carriage.

[0147] Referring next to FIG. 5, again a substantially continuous web 134 is shown. Further, a single print bar 166 is shown which extends across the full width of the web 134. This printer outputs the images for the separate jobs A, B, C, D organised onto the web in batches which group across the width of the web, rather than just along its length. This allows singular transverse cuts 172 to be used prior to longitudinal cuts for separating the substantially continuous web into stackable, or downstream processable, units (assuming that C and D have the same length). Again, however, the lengths of products A, B, C and D are not all common so screen printing is again unlikely to be useable.

[0148] Although only a single line of images B are shown, it is more probable that many hundreds of such images B would be presented sequentially. However, this image is just a schematic and is not intended to be representative of actual product order quantities (although such small batches are conceivably possible).

[0149] In FIG. 5, images C and D are shown arranged side-by-side. This is again just illustrative of the flexibility provided by the digital print bar.

[0150] Referring next FIG. 6, a further substantially continuous web 134 is shown being printed by a digital printer arrangement. Here, however, there are two digital printers arranged substantially side-by-side across the full width of the web 134. Each digital printer illustrated is fractionally wider than half the width of the web, so they are parallel but overlapping. An example for a 2 m web, could be two Hewlett Packard T 400 colour inkjet web press printers, each being 42 inches wide and capable of printing paper feeding through it at 180 mpm.

[0151] In this arrangement, each printer 166 is mounted upon a carriage (not shown) to allow it to traverse 174 at least partially across the width of the web 134. This ability to traverse offers no function in the print jobs illustrated in FIG. 6, since each combination of print jobs being printed by each respective printer 166 is adequately accommodated by the printer 166 in its fixed default position, as illustrated. Therefore, the left-hand printer 166 has printed print job C in two lines of side-by-side images and is currently printing print job A also in two lines of side-by-side images. The right-hand side printer, however, is printing a larger image run B, and has already completed an area print run D.

[0152] Again the solid continuous line 170 is shown for allowing indexing of a cutting arrangement further down the system.

[0153] This figure additionally shows a second solid continuous line 170printed by the second printer 166. The second indexing line is recommended to be provided where two printers are running together since each printer may not be perfectly indexed relative to the other printer, whereby an indexing line provided by one printer might not be perfectly aligned for the print run generated on the second printer.

[0154] Referring then to FIG. 7 a further arrangement is shown which further illustrates the flexibility of the digital printer arrangement of FIG. 6, and specifically the use of two digital printers, each mounted on a carriage for transverse movement relative to the web.

[0155] As shown in FIG. 7, two print runs A, B are being run at the same time, one by a left-hand print bar 166 and the second by the right-hand print bar 166. The first print bar 166 is printing a single print run having an image A, but with predefined waste edges 176 that will be cut away by longitudinal cutters 152 similar to the single blade cutter of FIG. 8 (typically there will be multiple independently moveable cuter blades). Around the image A, however, there are unprinted portions, which also form part of the productthe image covers only a part of the product. As such the print bar in theory can print an image for a product that is wider than the print barwhere the image is smaller than that product.

[0156] This concept is taken further by the second printer 166, which is actually printing two images, each defining a part of a further stackable unit 146. These two stackable units also have unprinted portions around their edges whereby the combined width of the two printed products (with the trim area therebetween) exceeds the width of the printer. This is achieved since the printer only needs to print the images, not the whole product, so as the images thereon together have a total width narrower than the printer, this product arrangement is within the printing capacity of the printer.

[0157] This capacity for wider product printing is further improved by the movability of the printersthis has allowed the right hand (second) printer to be away from the edge of the web. Had the printer 166 been positioned at the edge of the web 134, as per the left hand printer 166, the right hand printer 166 would not have been able to print both images. Therefore, by having the printers traversable relative to the web a wider variety of products can be printed by the non-full width printers.

[0158] It should also be appreciated that some of the relative movements between the printers and the web may be more beneficially achieved by moving the web relative to the rollers over which the web passes (either instead of or in addition to moving the printers relative to the rollers). This can have benefits since such web movements can be achieved very rapidly, whereas movement of the printers may need to be done more slowly since the printers may be inadequately robust to permit rapid sideways movements. Nevertheless, it can frequently be the case that one printer needs to be moved relative to the other printer, whereby movement of the printers themselves becomes useful and preferred.

[0159] Once printed, the web can be rolled for later processing (or if it is in-line it can be passed downstream to the downstream processing units).

[0160] Referring next to FIG. 9, a new feature of the present invention is showna reel map. Before now, such reel maps have not been needed or contemplated.

[0161] Standard operations practice has been for the corrugator/sheet processing apparatus 120 to be operated to produce a number (quantity) of products (boards/blanks) for meeting an order. There can then be a pre-programmed order change function (preprogrammed to occur at the completion of the order, i.e. after the target quantity was completed). These order change functions can be as simple as a prearranged cutter position change where there is no printed image, or where the image is unchanging between subsequent orders, or a switch out/splicing in of different layers when the sheet materials (or images) are to change, or a change in the corrugation settings when it is to be a change in corrugate form. Further, where automatable, these functions can often occur without operator input (the change-over rolls may be preloaded on standby, as are any alternate cutting arrangements).

[0162] This is all relatively straightforward when the printed paper is undamaged and when the corrugator all works correctly, whereby the initially produced quantity of products is correct for the first order, and of an approvable quality. However, when there is an error or problem, an operator would need to intervene, slowing down the feed speed where needed and overriding the order change function to prevent it from happening in the pre-programmed manner.

[0163] The form of the error or problem can have different consequences, but commonly if the boards have merely been damaged during production (something that is often noted when initial set-up tests are undertaken by looking at the product output), the operator can simply allow the apparatus to produce more of the products of the initial orderi.e. more than the initial intended quantityfor replacing the damaged products. However, this is only achievable while enough relevant paper remains on the wet end (i.e. upstream).

[0164] To allow for this additional images may have been pre-printed on the printed roll (and since there is less opportunity to alter the image when using a screen print, it is commonly the case that there would be many additional printed images as the whole roll may have been pre-printedready for repeat orders later on). However, it is also necessary for all the webs to be adequately and appropriately provisioned for the further products, and that might not be the case when they were intended to be switched out and replaced by a spliced in alternate for the next order. This process is thus undesirably inefficient on occasions.

[0165] Further, when using digital printing, the roll does not have numerous spare images. Instead it has an order set, and then subsequent order sets. As such the image changes along the roll, so running off further products is unlikely to be possible. As a consequence the order change function MUST occur when the initial pre-programmed quantity is completed (or when that part of the roll is reached). After all, thereafter the image will change on the outer liner.

[0166] Yet further, the inner liner and fluting papers typically need to order change before the outer liner (printed reel). This is to allow for the paper contained on the bridge and also the distance between the Single Facer and Double Backer.

[0167] A Reel Map is therefore a new concept that allows the corrugator to react to order changes before they are reached on the outer liner. It is a map or reference stored electronically in a control system of the corrugator/sheet processing apparatus and is effectively a look-up reference linking to a database of the various order parameters in a central repository. It provides a readable reference of the known or expected layout of the images on the digitally printed roll.

[0168] It works alongside Intelligent Marks or information markers that are printed actually onto the rollin this example one for each image or artwork, and thus one for each product. The map additionally indicates approximately where on the roll the markers are positionedherein in a rearward corner of each image, but in an area that will be trimmed away from the final product. See FIG. 10 for a more detailed illustration of possible locations on the roll.

[0169] The reel map thus provides a database of the markers, and what their images or artworks should look like, and their relative position in the orderi.e. first, second, third, lase, 10 from the end, etc. Likewise it will enable an anticipation of order changeschanges in the cutter settings and the liketo be provided as the real-time movement of the reel can be monitored and validated against the reel map to confirm there is no problem, with the reel map being a means for the control system to know where in the order the machine has got to, and to verify it against the readings from the markers. For that purpose a marker scanner is provided on the sheet processing apparatus/corrugator.

[0170] To allow the marker to relate to positions within the reel map, and thus perform a validation of the position of the reel/order/product, the marker will generally have two pieces of information: an order number or order code, also known as a CBS Step number, and a sequential indicator illustrative of the position within the order, such as a number between 1 and 999,999. As the number of printed images can be recorded in the reel map or database, that latter part, even as a number, can give the indication of where in the order the present marker sits, with the former part of the marker then additionally identifying the order. When read, the reel map can confirm that the read information is the expected information, thus confirming the position of the reel.

[0171] The information marker can be as simple as a number such as nnnnnnn-nnnnnn, where n represents a number. Preferably, however, the number is encoded into a rapidly readable format, such as a barcode or QR codeelectronic scanners can read such encoded markers more efficiently than a straight string of numbers. A sample QR code is shown in enlarged form in FIG. 9.

[0172] It is desirable for the marker to fit inside a glue lap trim area of the artwork or inside the die cut tray trim area, or in some other waste part of the area surrounding a product. See, for example, FIG. 10 where the markers 50 are so positioned. It is also desirable that there be a marker for every image or artwork, as shown in FIG. 9 and in FIG. 10. This enables a very efficient and accurate tracking and checking of the position of the reel, and since the images can be of a significant size, such as over 1 m long in the case of some cardboard boxes, that close monitoring of the position has advantagesless wasted material passes through the machine between inspections and thus detected errors can only relate to a smaller amount of waste. It is also desirable for every marker on a roll, and potentially across all rolls within a defined area, be uniquely identifiable.

[0173] Referring next to FIGS. 11 to 13, the usefulness of the adaptability of the reel map is illustrated.

[0174] The table represents a reel map, and it has various columns representing the parts of the information markersa order identifier (column 2 and 5) and a position identifier (columns 1 and 6). It also indicates particular jobs but as can be seen an order can comprise two separate jobs where they can be printed side by side, herein A and B, C and D and E and A, so more than one job can then have a common order identifier (herein 1, 2, 3). Further, the position identifier can be a count from the start of the printing on the roll, rather than restarting for each orderthis is optional as position within the roll can be ascertained from either that count or the reel map as the order of the print orders is known from the reel map anyway.

[0175] It is also noted that an actual order can also be split into partse.g. A with B and A also, later, with E. This flexibility can allow greater efficiencies in the positioning of the orders on the roll of paper. It also allows downstream errors (such as corrugator failures) to be corrected as replacement images can be fitted in where appropriate onto rolls for orders using similar paper setups.

[0176] The reel map in FIG. 11 therefore shows the order in which the images are printed onto the roll. The reel map and the roll of paper therefore should match, and identification markers allow that to be checked. However, while printing the roll of paper, a quality control inspection of the image was carried out and errors in the images in rows 17 to 21 were notedthis error is reflected by emboldened print in FIG. 11. Those images thus will not be suitable for producing products. The reel map marks this by highlighting those rows as shown in FIG. 12.

[0177] To prevent foreseeable downstream wastage (the paper that would be used to form the board onto which the images are laminated, and which would have to be discarded later on if used) it is desirable to remove the bad images from the roll of paper. Thus, the printed reel is spooled onto a new core until the relevant section is reached and a cut is made so that the waste section can be run off into a shredder until good print resumes. Another cut is then made to remove the end of the waste and the two ends of the good sections are spliced together. This alteration is then likewise recorded in the reel map as shown in FIG. 13 where the first and sixth columns no longer record rows 17 to 21 as images, but instead record a splice at row 21 and record no image at rows 17 to 20 (as they were cut out). The reel map thus now again records a correct representation of the images.

[0178] The spooling also is not an additional step anyway as the printed roll typically needs to be spooled back anyway to get its order correct for processing on the corrugator (unless it was first printed in reverse).

[0179] As the reel map is now correctly reflecting the images on the roll of paper, when that roll is to be processed, the reel map can be accessed by the control system of the corrugator/sheet processing apparatus. The corrugator progresses through the roll and the plan, and both will match.

[0180] The first significant order change for the corrugator then to react to change is the order change at position 8 (first column, FIG. 13). The corrugator is able to order change the single facer at position 6, prior to the order change of the outer liner at position 8. This then ensures that the papers match and splices are contained within the order change section of the board. The need to change is thus foreseen and the change can occur with minimal waste at the change-over.

[0181] Should the corrugator stop or misfeed, or a paper break be experienced, the corrugator must be able to start up and synchronise with the reel map again as soon as possible. The intelligent marks will enable this as they will link to the reel map so that position within the reel can be established simply by reading the information marker on an image and finding that image on the reel map. As shown in FIG. 14, where this stop or break is in the middle of an order, the effectively chopped out portion simply loses some of the order. However, when the processing resumes, the layers running in the corrugator, and the cutting arrangement's setup, will still be appropriate for the order. The system thus can quickly resume and find its place for ensuring that order changes occur at the correct point of the rolls. However, as seen in FIG. 15, the stop can occur at a position on the roll that bridges across two different orders. As a consequence, the cutting arrangements are likely to be wrong, and the papers might be too. In this circumstance it is likely that an operator will need to intervene to force a manual code change function to update the cutting arrangement or paper settings.

[0182] The present invention as described and claimed therefore enables a more automated tracking of a print roll, and the ability better to correct for errors or problems, and with less operator interaction. It also offers greater flexibility in the print layout and thus a more efficient use of the paper. It also facilitates more specific inventory control as there are the reel maps keeping an accurate record of the images printed on the various reels in stock. It also facilitates a reduction in waste when errors are noted in the printing of the rolls.

[0183] Referring next to FIG. 16, a wet end of a corrugator is shown. As can be seen the corrugator has six supply rolls 1A, 1 B, 2A, 2B, 3A and 3B, a facer unit 200, a camera 300 and a backer unit 400. In the facer unit 200, a first web or sheet 210 is taken from one of the supply rolls (2A or 2B) and is combined with a second web or sheet 220 taken from a second supply roll (3A or 3B). Before combining them, one of the webs or sheets (210, 220) is corrugated so that as shown in FIG. 18, the output faced sheet 230 is a corrugated layer with a flat facing sheet.

[0184] Then in the backer unit 400, or as shown, in a combiner unit 500, that output faced sheet 230 is combined with a third sheet or web 240, taken from a third roll (1A or 1 B), to form the backed and faced corrugate from which products can be cutsee, e.g. FIG. 20, which shows post-corrugation processing equipment, or dry end processing equipment, such as cutting or stamping equipment. Note too, that further corrugated layers may be applied elsewhere in the apparatusFIG. 19, for example, shows a corrugator for forming a corrugate having a top sheet, a middle sheet and a bottom sheet, plus two corrugated layers separating those sheets. It likewise can feed the dry end processing equipment of FIG. 20.

[0185] Referring back to FIG. 17, it can be seen that a camera is mounted for inspecting one of the sheets of the corrugateda printed layer. In this example, the printed layer is a bottom layer of the formed corrugate. FIG. 2 instead showed the top layer to be printed. Important, however, is that one of the sheets, inspectable by a camera, is printed, as the printing enables the tracking of the position of the layer by the control system of the inventionthe camera inspects printed information markers, as previously described, for enabling a data look-up table to provide trackability.

[0186] The digitally printed reels are shown loaded at positions 1A and 1 B, although they could instead be loaded at positions 3A and 3B, e.g. for use for the inside of the box. Reels at 2A and 2B are the fluting, and as that is faced by the other sheets, it is unlikely to ever be printed, although it might be for further tracking purposes.

[0187] Because the information markers are printed onto the sheet that is being inspected, a reel map for that sheet can be referenced (i.e. the look-up table can be consulted), so as to know the position along the reel at which the camera is currently inspecting. As that position will be a particular position within a product run, it will be known, as described above, what cutting requirements will be later needed for that position, so as the sheet feeds forwards the cutters can be adjusted appropriately. That relates to a dry end benefit from the information markers. The present invention also provides for a wet end benefit, however, in that it will also be known how many more product images will be presented before the next product run starts. It can thus be determined if a splicing unit needs to be activated to change the source material for that next product run, and the timing of that change can also be coordinated so that the splicing operation only happens at the print-change position. For the purpose of that splicing operation, there are two rolls provided for each of the three layers of the corrugate, and thus the materials from the rolls can be swapped over when needed. The sheets for the corrugate are thus changeable. This in turn can then be used to ensure that the required change of papers on reel stands 2 and 3 are synchronised with the order change on the printed media on reel stand 1.

[0188] This wet end tracking has particular benefits for the wet end as slack can form on the bridges 600 (see FIG. 19) within the wet end, thus making the timing of the cutting at the dry end less discernible from the information markers if they are being read at the wet endthe cutting occurs further downstream, after the bridges, and within the dry end, so cameras are again provided for the dry end, e.g. after the bridges, or within the dry ende.g. after the corrugate is formed.

[0189] Various preferred features of the present invention has been described above purely by way of example. Modifications in detail may be made to the invention within the scope of the claims appended hereto.