Method and apparatus for facilitating the printing of verso sides and the varnishing of recto sides of sheets

US5309839A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Georg Hartung · Seligenstadt, DE
• Michael Rother · Rödermark, DE

Key dates

• Filing date: Apr 7, 1993
• Grant date: May 10, 1994
• Expiry date: Apr 7, 2013

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41F23/08
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Method and apparatus for the varnishing and printing of sheets in a printing machine. A feed drum incorporates a counterpressure surface to form a first nip with an impression cylinder. As sheets are fed to the impression cylinder and transported through the first nip, a constant pressure at the first nip consistently transfers ink to a verso side of each sheet. Arranged thereafter, a varnishing cylinder supplied with a quantity of varnish contacts the impression cylinder creating a second nip. As the sheet passes through the second nip, the recto side of the sheet is coated with the varnish. The impression cylinder thus receives a constant pressure for transferring ink to the sheet independent of the pressure provided by the varnishing cylinder. Accordingly, even a partial or intermittent varnishing of the recto sheet side has no adverse effect on print quality, and the sheet does not have to be transferred from the impression cylinder to a separate varnishing unit.