Method for detecting films

US5761999A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Andreas Lippold · Nidderau, DE
• Christian Schlegel · Dietzenbach, DE

Key dates

• Filing date: Oct 11, 1996
• Grant date: Jun 9, 1998
• Expiry date: Oct 11, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S101/45
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to a method and device for detecting ink or lacquer films on metallic surfaces inside printing machines. In particular, to irradiate the surface with light and sensing of the intensity of the reflected light to detect whether an ink film or lacquer film on a roller has been completely removed by applying a metering element or doctor-blade element. This is achieved according to the invention by the irradiation of the metallic surface or of the film located thereon, and the reception of the light reflected from the surface or the film located thereon is performed at the Brewster angle with respect to the surface normal, the Brewster angle being defined by the refractive index of the material of the film to be determined and that liner polarization of the light is performed at least partially in the plane of incidence, at least in one of the two beam paths.