Once again, we’re lucky to have a post by Bruce Watermann, Senior Vice President of Print Operations and our resident guru of all things print. Read on to learn the inner workings of our newly improved, super strong PUR book bindings.
We’ve been talking a lot of late about Blurb’s obsession with quality and where it really shines is in our binding. We recently announced a move to a continuous, seamless end sheet and the response has been great. But these new end sheets are the cosmetic face of what has been an ongoing evolution of our print-on-demand (POD) books. The technology that allows the new end sheet also makes for a stronger, more environmentally-friendly, and aesthetically pleasing book that also has a bit less “spring” than our old, side sewn books.
I talked about this improved process using PUR (Polyurethane Reactive) glue in an earlier post. But how exactly do we bind our books and what makes the process we use different from commercial offset printers? Read on.
The PUR gluing process emerged from the perfect binding workflow. Originally perfect binding, like what you generally see in paperback books, was developed using hot glue, or EVA (Ethylene Vinyl Acetate) – the same sort of glue you find in glue sticks. EVA creates a quick drying, sturdy bind but does not have much flexibility. PUR glue, on the other hand, is a cold glue that has much more flexibility – something that is required when you introduce a hard cover hinge to the binding.
The process is completed using an automated binding machine and has several steps. First, the book block of book pages is measured for thickness using an integrated caliper device. This is a bit different in the POD world since every book is unique as opposed to setting up a machine and running thousands of copies in a single run. Second, the binding edge of the paper is milled using a saw-blade-like device. This exposes the fibers of the paper, allowing for optimum glue penetration and adherence. Third, the book block is coated with the PUR glue on the spine and both sides. Fourth, the end sheet is introduced, aligned with the book block, and “nipped” to complete the gluing process. The book blocks are then allowed to cure before casing-in the hard covers, either linen or ImageWrap.
The end result is the beautiful, sturdy bindings you’ve been seeing if you are in North America or Australia for the past few weeks. The PUR bindings are due to go live in Europe very soon. We’re proud of our continuing advances in the art and craft of bookbinding, and I’m sure you’ll be proud to show your Blurb book to friends, colleagues, and customers for years to come.
Thanks, Bruce. Blurbarians, watch this space for more guest posts by the Blurb team in the coming weeks.