Mechanism for controlling and smoothing a conveyed sheet in a multi-color printing press particularly applicable to printing in the verso mode

US4222326A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Josef Mathes · Offenbach, DE
• Rudolf Melzer · Großkrotzenburg, DE

Key dates

• Filing date: Feb 27, 1979
• Grant date: Sep 16, 1980
• Expiry date: Feb 27, 1999

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41F21/00
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A multi-color printing press including a first press unit and a second press unit with a conveyor interposed between them, the conveyor including a sprocket drum cooperating with a transfer drum on the second press unit. A pair of plenums having apertured faces alined with one another are arranged closely adjacent the feed side of the sprocket drum, the plenums being connected to a source of vacuum. The plenums are cammingly coupled to the press drive for axial spreading movement during passage of a sheet so that the faces of the plenums progressively wipe away any longitudinally extending as well as laterally extending wrinkles in the sheet as the sheet becomes progressively supported on the sprocket drum for sequential passage of the sheet in smooth condition and in accurate register via the sprocket and transfer drums, the action of the plenums being effective both in the recto and verso printing modes. A further cammed connection is provided for supporting the plenums with their faces spaced from the surface of the sprocket cylinder and for cyclically lowering the plenums into close proximity to the sprocket drum during passage of each sheet.