Heidelberger Druckmaschinen Ag

Raimund Schroeder

Daniel Conzelmann

Wolfgang Dolz

Arno Juenger

Thomas Schmidt

Alexander Knabe

Albert Maul

Kai Oskar Mueller

Juergen Rothaug

Sven Goll

A sheet-transporting drum includes sheet-supporting areas each being formed of a first comb segment and a second comb segment having segment teeth. At least one of the comb segments is rotatable for adaptation to a sheet format. A mechanical leading-edge gripper is provided on the first comb segment and a pneumatic trailing-edge gripper is provided on the second comb segment. A mechanical trailing-edge gripper is additionally disposed on the second comb segment and is deactivatable in particular by format adjustments. This advantageously allows either the trailing edge of a sheet to be securely held down mechanically or a full-bleed print to be applied to the sheet when the trailing edge of the sheet is held down pneumatically. A sheet-fed printing machine is also provided.

Sheet-transporting drum and printing machine having the sheet-transporting drum

A sheet-transport drum includes at least two sheet-supporting surfaces with suction openings. Each respective sheet-supporting surface is formed of first and second comb segments with segment teeth. Suction grooves are provided in the segment teeth and a trailing-edge suction groove is provided in the sheet-supporting surface of each respective second comb segment. A rotary valve is provided for a timed supply of suction air. A plurality of vacuum sources is provided and a trailing-edge suction groove is assigned to each respective vacuum source by the rotary valve. This ensures that the vacuum provided by a respective trailing-edge suction groove at the trailing edge of a respective sheet is reliably maintained even if a previous or following sheet is missing. A sheet-fed printing machine with the sheet-transport drum is also provided.

Sheet-transport drum and printing machine with a sheet-transport drum

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Hockenheim, Germany

Raimund Schroeder