Michael N Perreault

US Patent:

6684776, Feb 3, 2004

Filed:

Feb 23, 2001

Appl. No.:

09/795076

Inventors:

Kevin Lauren Cote - Durham NH
Neil Doherty - Durham NH
Michael Roger Perreault - Rochester NH
Lothar John Schroeder - Portsmouth NH

Assignee:

Heidelberger Druckmaschinen AG - Heidelberg

International Classification:

B41F 1354

US Classification:

101228, 101219

Abstract:

A method for determining the presence of slipping of a driven nip roller relative to the web in a web printing press includes systematically changing the speed of the nip driver while monitoring the corresponding change in web tension difference across the nip. The linearity and a slope of the relationship between the tension difference and the speed of the nip driver are determined. When the tension difference is non-linear relative to the speed of the driver or the slope of the relationship is substantially less than an expected slope, then slipping is determined to be present. An operator slip indication may be provided which includes the direction of the slip, positive or negative. The operator may then take corrective action to re-establish a non-slip condition, or automatic corrective actions may ensue.