Paper welding apparatus for bookbinding machinery

Apparatus for binding books by welding paper sheets together including in combination clamping jaws for applying a stationary pressure to a group of paper sheets in contact with each other along regions that constitute edges of pages printed on said sheets, means for heating the paper along said regions including a radio-frequency generator, connections through which radio-frequency power from the generator can generate paper-welding heat in the clamped edges of the sheets, means for changing the heat for welding in accordance with the thickness of the group of sheets, with which the apparatus is used, to raise the clamped edges to a welding temperature of the paper and a limited temperature that avoids overheating and scorching of the paper sheets, and means for urging the clamped jaws together, the means urging the clamping jaws together having their force coordinated with the power supply from the radio-frequency generator to the paper so that the pressure between adjacent sheets of paper is high enough to prevent flashover of the radio-frequency power between adjacent sheets.