Patent ID: 7096784

Claim:
An installation for treating sheets of paper printed on both sides, especially papers of value, comprising: a sheet-by-sheet feed device, transfer means, means for treating said sheets, and means for separation of the sheets into at least two separate stacks, wherein said means for treating the sheets comprise the series arrangement of first quality checking means for checking the printing quality of the sheets, printing means for numbering the sheets and/or printing additional elements on the sheets following passage of the sheets through the first quality checking means, second quality checking means for checking the printing quality of the numbering and/or of the additional elements, and marking means for marking the sheets found to be unacceptable by one said first and/or second quality checking means; the first quality checking means further comprising a first group of rotary sheet-seizing members rotating about a first axis of rotation and a second group of rotary sheet-seizing members rotating about a second axis of rotation, parallel to the first axis of rotation, the rotation of the first and second groups of rotary sheet-seizing members being in opposite directions and in synchronism, passage of a sheet from the first group of rotary sheet-seizing members to the second group of rotary sheet-seizing members taking place along a contact generatrix of circular paths described by said rotary sheet-seizing members so that each sheet follows approximately an S-shaped path, each side of the sheets being presented in succession to first and second optoelectronic reflection-based checking devices; and the first optoelectronic reflection-based checking device being located inside the circular path traveled by a sheet about the first axis of rotation, the second optoelectronic reflection-based checking device being located inside the circular path traveled by a sheet about the second axis of rotation, an optoelectronic transmission-based checking device being located inside of one of said circular paths.