Folded signatures are placed over a "saddle" and then stapled along the spine. This style of binding is excellent for booklets, brochures, newsletters, pamphlets, direct mailers and catalogs. Page numbers have to be in multiples of 4 to make the folded booklet. As few as 8 pages with cover can be used or up to 64 with self-cover.
The printed and folded signatures are first gathered together. The cover is scored to the thickness of the spine, creating a channel or groove for the gathered signatures. The gathered signatures are pressed together and the bind edge is ground to expose the paper's fibers, hot glue is applied to the roughened edge, and then the cover is joined to the signatures and clamped until dry. The bound books are then trimmed on three sides and finished.
Plastic comb binders first punch the holes in the paper. The binding comb is then inserted in the binding machine. The comb binder's handle is pulled, opening the combs to allow placement of the paper through the combs. When the plastic comb is closed, the paper is bound together.