Finishing Web Inkjet Printing, Part 1
This is the first installment of a 2-part series on web inkjet finishing. This installment will cover the tactical considerations that need to be considered when building your finishing line, and the next installment will be the more strategic question of whether your system components should be in-line or near-line.
The thought of moving to high speed color inkjet printing is very seductive, with the availability of fully variable images, continuously improving quality, runs as short as quantity of one, and the nearly non-existent expense of make-ready, but there is a lot to analyze and decide after making a decision to do it.
After you decide on a printing technology and vendor, the next biggest consideration is finishing. High speed color inkjet printers are web fed, and there needs to be all of the cut/stack/fold/bind operations that any web printing process requires. But these processes are handled differently because of the differences in how digital print creates a finished piece as compared to traditional offset printing. As you are aware, the digital printing process prints one complete book or mailpiece at a time, minimizing or eliminating the need for collating. Depending on your end products, there are some strategic decisions to make, and some tactical ones, too.
The tactical decisions are the end-product-specific things that you need to finish your printed piece: Do you need to perforate, punch, stack, slit, slit-then-merge 2 or 3 webs, or fold? Your finishing vendor can determine the modules and accessories you need based on your product descriptions, and these selections are generally fairly straightforward.
Perfing/punching decisions are broken into two parts: Static punching and perforating usually gets placed before the first print engine. This is a device that allows you to create the tractor or pin-feed holes along the outside edges of the paper, and cross perfs at each page if you have legacy bursting/folding equipment that you need to use. Don’t forget the web cleaner so that chads and paper dust is minimized going into the print engine.
Dynamic punching and perfing can be triggered by either barcodes or other queue marks that are inserted in the margins by the print file and give you the flexibility of placing horizontal and vertical perforations, either partial or full width, on only selected pages.
Then you need to understand how you are going to bind. If you come from traditional printing, binding is a bit different in the digital world, since you can print an entire book or other document sequentially. As a result, little or no collation is necessary, except for getting covers on publications and books, or getting your printed stack into an envelope. So your standard pocket-style binders or inserters are generally not going to be suited for this new product stream. You will need to investigate binding devices that will handle the new product stream. Again, your binding equipment vendor can help you make this selection based on your end product. The considerations for digital print binding are much broader than they were just a few years ago, with choices that include stitching, perfect binding and even a cold-glue binding option.
Now that you have the right components and modules to finish your product, you need to decide whether they should all run as a single production line, allowing you to load roll paper in one end and out comes a finished book, mailpiece, or other product, or break the line up into two or more pieces. That issue we will discuss in the next installment.
Just us next week for Part 2 of this post!