Can You Do Variable?
I often get calls from printers (and binderies) asking about that "smart" saddle-stitcher that they've heard about. Full disclosure, I'm talking about the IBIS Smart-binder, which I sell in the United States and Canada. And this is the machine they're usually referring to. The difference between what they know (a conventional saddle stitcher) and the unique IBIS machine is substantial. I can visualize tiny lights going on in their heads as I explain the Smart-binder's unique technology.
In a conventional offset saddle-stitcher, you have a gathering section that gathers offset-printed signatures one on top of the other (plus an optional cover sheet) to make a finished book. The collection is stitched and trimmed to produce a finished booklet. These machines have a very limited ability to vary the number of signatures from book to book. And large variations in number of signatures will require the operators to stop and make adjustments to the three-knife trimmer.
The digital process eliminates signatures altogether. In fact, it eliminates work-in-progress, the staging of signatures between press and bindery. Digital saddle-stitchers like the IBIS Smart-binder are designed to accept printed sheets directly from the digital press or roll unwinder. They are designed to be able to process completely variable page-count booklets. The Smart-binder, for example, can produce a four- to 200-page finished booklet with no adjustments needed from the operator.
How does it do this? First, the Smart-binder processes the work as individual four-page sheets. Each sheet gets individually scored and folded. This process yields a high-quality finished (unbound) book. Second, it can use a patented cold-glue system to apply a micro-pattern of cold glue to each sheet. The sheets are then pressed together. This forms a bond that is even stronger than wire stitching. In this process, there is no stitcher wire adjustment to make for different page counts, so a varying number of sheets can be collected, one after another.
But perhaps the most important feature is the Smart-binder's three-knife trimmer. Conventional three-knife trimmers are "flat.” That is, they are horizontal and use pressure belts to transport the book through the trimmer. In this case, large variations in page counts will need a manual increase or decrease in the belt pressure on the book, requiring the operator to stop the machine and adjust the trimmer belts.
The Smart-binder's trimmer, on the other hand, is built on an angle. It was designed so that gravity helps register each book against the knife stops without the need for over-running transport belts. In the new Smart-binder SB Plus HS, a specially-designed transport belt assembly was added to increase cycling speed to 7,000 cycles/hr. but these belts are not required to overdrive the books against the backstops, and they do not need adjustment when book thickness changes.
These machine features permit the Smart-binder to continually process personalized booklets with highly variable page counts, without stopping for adjustment between booklets. This makes it ideally suited to the new "variable" workflow of the digital world.