DIGITAL PRINTING THROWS THE SPOTLIGHT ON THE finishing process as never before. Arguably how a product is completed becomes more important than how it is printed. Some commercial printers are beginning to realise this and work to minimise set up time in the bindery through better planning and automation, but few would consider allowing the finishing process to drive the rest of the factory. That though is what is going to happen as digital printing, represented by the high speed inkjet presses from Kodak, HP and the rest, takes hold.
At exhibition outings these machines are demonstrated in reel to reel mode as if printing were everything. But the vital step of turning the printed page into a deliverable product is missing. In sheetfed digital printing, the gap is already being filled. At the Printing Alliance event in London last month, Duplo showed a System 5000 bookletmaker set up to count, collate, fold and stitch A4 products with variable information and personalised to suit subscribers to a financial product. barcodes are used to identify the pages needed by each recipient. These are used to ensure the integrity of the product and to provide an audit of what has been printed and when, and also which need to be reprinted because that copy was rejected for lack of a stitch, a missed sheet or bad fold. This can then be called off the press for a second printing. Pete Dyson explained that the advantage is that the printed can prove what has been printed and delivered to the post if and when the customer asks for this. However, there is no standard he said that will allow the finishing line to automatically call off additional copies should one be rejected. This is still a manual process. Horizon is in a similar position. Its StitchLiner can count pages as they go in and knows which have failed to be reordered, but it cannot complete the circle by triggering a new print request.
This is only a minor irritation in sheetfed production where scale and speeds allow human intervention.
There are other examples where sheetfed digital is thinking much harder about linking to the finishing element, having for many years argued that putting finishing into the machine, as those supplying inplants have been wont to do, caused more problems than it solved. The growth of sectors like photobooks has placed the emphasis on productivity and led to varnishing units appearing in line with presses, and in packaging lines with die cutting technology in line with the press. As sheetfed digital is being more productive, industrial thinking is taking hold.
IN PROCESSING WEB FED DIGITAL PRINTING THIS IS ESSENTIAL, individual products need to be controlled from start to finish on the process. In existing applications, transactional printing for example, much of this integrity is provided at the mailing end. Scanners and readers check that the envelope matches the contents and that the correct invoice is being sent to the correct address.
With greater levels of sophistication, new types of code provide greater amounts of data and allow more sophisticated products to be produced, while video control as the piece is being printed, checks that all the elements of a page are in place. Hunkeler demonstrated this at its Innovation Days in 2009. This can sort pieces ahead of any mailing system causing only good products to go forward and providing a report of what has been printed. Again this has been developed to cope with evolution from mono to colour printing in the transactional space. But for digital printing to succeed as those designing the print engines hope, finishing in line has to manage a much wider range of product types, including multi-section products like books, magazines and catalogues.
The book issue is being addressed by a number of solutions. On the one hand Hunkeler can slit and stack book blocks ready for binding. Equally Canadian company Magnum has produced a system capable of working with 30in webs and thanks to a modular approach will be able to cope with even wider presses as they arrive. UK book press producer Timson has also developed a means of creating book blocks from webfed digital presses. And Muller Martini has shown that its Sigmaline can produce books inline with digital web presses. This is the set up at Clays where a Sigmaline operates in line to a Versamark inkjet press. It also has customers in Bell & Bain in Scotland, RR Donnelley and Rotolito Lombarda in Italy where it connects to an HP T300 inkjet web.
However, while Sigmaline has been considered a means of delivering collated book blocks from digital web presses, perhaps linking to one of its binding lines, the possibilities extend well beyond this. Sigmaline, or something like it is going to be essential if HP and Kodak mean to extend the footprint of digital colour printing beyond direct mail, books and transpromo.
AT THE HEART OF THE SIGMALINE IS THE CONNEX WORKFLOW. While this is also the management system that links other Muller Martini saddlestitchers and perfect binders into a JDF-based production workflow, it was developed to drive Sigmaline and to meet the needs of next generation printing systems. Crucially this means that Connex is also capable of driving the printing press, closing a loop that remains open in sheetfed production.
The physical parts of a Sigmaline start with signature folders, as many as are needed for the web width. The module includes festoons to keep the web under the correct tension as it moves from press to finishing system. The folder itself delivers variable format signatures and as web widths increase, additional formers will continue to deliver folded sections rather than sheeted product.
The signatures are gathered in a stacker section, completed blocks identified by codes printed in the trim areas. The blocks are moved to a buffer area to compensate for the different speeds of the press and the binding system. The buffer will also allow the printing press to continue operating while the binder is stopped during madeready for the next job. Automated set up reduces this to a minimum, but cannot yet eliminate it. Once running the blocks are moved from the buffer via a lift to tilt them and load them into the binder’s feed section. Muller Martini expects users to specify a Panthera or Acora binder for digital print production, the highest speed models not being necessary. Covers can be drawn on and glued for soft cover production. The binders can use either hot melt or PUR gluing. An Esprit three knife trimmer and then stacker complete the line.
Equally end papers can be added for case bound books which will be finished in the Diamant casing-in line. All the production elements are designed for minimal makeready and also for maximum feedback to the Connex controller.
IT IS AN ENTIRELY MODULAR APPROACH IN WHICH DIFFERENT BUFFER SIZES can be specified, different sized binders or even a saddle stitcher included rather than perfect binder. Everything is controlled through the Connex. This is logical, because it is the finished product size that decides how many signatures are needed for each block, how many pages there are in each signature and therefore how those pages should be imposed and what marks are needed to track product and control the finishing process. Consequently Connex starts with a PDF of the complete job delivered from prepress. From this it creates the JDF file that controls the entire finishing process as the web is delivered from the press or unwound from the reel.
In the process, Connex adds cut marks and identification codes to the imposed PDF file that will be sent to the press. A dot matrix code will synchronise the folder settings and allow adjustments to be made on the fly. If the line is set up with choices on binder or to a stacker, the codes will manage this. At the same time a JMF file is sent to the overall production server or MIS that the printer has. The central system provides other data, run length for example, that are necessary for the final job. However it is Connex that controls the press. With all the data about the job, the finishing line and press, Connex will calculate the options for producing the job. A decision to work with 16pp sections will impact how those pages need to be arranged across the width of the press. Modules within Connex will create the imposition and deliver this to an EskoArtwork Backstage as part of the system. This creates the imposed PDFs needed by the press and builds the job queues which help decide the production sequence, so the jobs can be grouped according to paper type or by format to suit the finishing processes.
The dot matrix code will also identify each product feeding its position on the production line back to Connex. Crucially, if at any point the single product is rejected, the server will order an additional to be printed automatically, retaining any personalisation that forms part of the finished product.
THE CONNEX AND THE MODULES THAT COMPRISE THE SYSTEM can be split, some located in the bindery next to the line, some placed remotely in a production office. It means also that minimal labour is needed to run the line, taking another step towards automation of the printing process. It is early days yet for this type of system, but it is not inconceivable to have a Sigmaline linked to perfect binder or to sheeters to divert pages through a saddle sticther. The way then becomes clear for inkjet presses to print the sort of span of products that is needed for inkjet to make a truly significant impression on commercial printing.
NOVEMBER 2010
