Perfect binder

A perfect binder is a processing machine used in industrial bookbinding. Perfect binders are continuously working machines for gluing the pages, often also part of complete book flow lines .

In a perfect binder, book blocks are produced from the folded and collated printed sheets in several processing steps. Depending on whether this book block thereafter with a single-layer flexible envelope or a solid multi-layered book cover is connected, it is called the final product of a perfect bound paperback or perfect bound hardcover

The individual processing steps are as follows:

1. Alignment of the folded sheets at the top (top) and collar (back) by vibration.
2. Clamping the aligned book blocks between two transport clamps with the collar down.
3. the approx. 5–10 mm (depending on the machine manufacturer) protruding collar is milled off by approx. 2 - 6 mm so that the folded sheets are now open at the bottom.
4. Additional tools are used to clean off milling dust, finish and notch the surface for better adhesive absorption.
5. An adhesive layer is applied to the future book block spine by means of a roller or nozzle gluing unit.
6. there are (water-based) dispersion adhesive , hot melt adhesive (hot melt) adhesives or polyurethane basis (PUR) is used. PUR has the advantage of having particularly high holding forces and at the same time producing an easy-to-open book, since the layer of PUR can be particularly thin and the bending forces of the back are correspondingly low: the book remains open and does not break.
7. A flap strip is stuck onto the still fresh (“open”) adhesive , if the book block is to be bound later with a book cover to form a hardcover book.
8. If a brochure is to be created, side glue with a width of 4 to 10 mm is applied before the flap.

The book block is then placed directly in the center of the opened cover and pressed together with it. The envelope itself is usually four-fold.

After the adhesive binding, either only the book block (in the case of a later hardcover) or the entire brochure is trimmed on three sides (head, foot and front).

Under the conditions of the industrial mass production of books and brochures, adhesive binding is a very efficient technology; in practice, cycle rates of up to 15,000 blocks per hour are achieved. Nonetheless, the perfect binding process is very complex and requires fine tuning of the materials and processing parameters used in order to create durable products.