Two-shot hot-melt bookbinding

DETAILED DESCRIPTION OF THE INVENTION In the perfect binding of books and related articles, standard equipment is employed which generally can be used in conjunction with a variety of adhesives.
For example, the overall equipment or bookbinding line utilized in two-shot bookbinding is generally the same whether a hot-melt primer or an emulsion primer is used.
Referring to FIG.
1, a schematic representation of a bookbinding system 10 is given The system 10 is generally suitable for use with the two-shot hot-melt adhesives of the present invention.
However, as will be explained, use of the adhesives of the present invention, in conjunction with bookbinding system 10, offer certain operational and economic advantages when compared with prior art adhesives.
The page materials are printed in long continuous webs which are cut and folded into stacks or signatures and placed in proper sequence at a gathering station (not shown).
The collated signatures which form the body of the book are then clamped together within book clamps 12 positioned on a conveyor 13.
The gathered and clamped signatures form a book block 14 (FIG.
2) which is typically conveyed by a conveyor 13 to a backbone preparation station 16 where saws 18, a rougher/raker 20 and a notcher/slitter 22 further prepare the sheets for application of the adhesives.
The saws 18 cut the free edges of the clamped sheets to remove the folds from the signatures.
The rougher/raker 20 and notcher/slitter 22 rough the backbone or spine of the book to expose a maximum amount of paper fibers.
In this manner, the adhesives will be better able to penetrate the paper fibers to form an effective bond.
Referring now to FIG.
2, illustration is made of a book block 14 having its backbone or spine 28 prepared in the manner described above.
From the backbone preparation station 16, the clamped pages are conveyed to a hot-melt primer pot 24 for application of primer adhesives by dual glue wheels 26.
As will be appreciated by those skilled in the art, the wheels 26 generally rotate in mutually opposite directions and apply a measured amount of pressure when applying the primer to the backbone of the book block 14