Apparatus and method for lateral belt control with backlash compensation

A method for detecting and correcting steering system backlash of an moving web about a predetermined path, comprising:

• a.) tilting a steering roll by an angle .THETA..sub.1 about a steering axis in a first direction so that the web moves in a second direction;
• b.) tilting the steering roll by an angle .theta..sub.1 about the steering axis in a direction opposite to the first direction, wherein .theta..sub.1 is a fraction of .THETA..sub.1 ;
• c.) repeating step b until the web moves in the direction opposite the second direction;
• and
• d.) determining backlash about the steering axis in the first direction as a function of angle .theta..sub.1 and the number of times step c is repeated.

An electrophotographic printing machine of the type having an endless belt arranged to move along a path in a predetermined direction, including:

• a belt steering roll for supporting said belt, said belt steering roll being adapted for rotational movement about a longitudinal axis and tilting movement about a second axis transverse to the longitudinal axis;
• means, responsive to movement of the belt in a direction substantially normal to the predetermined path, for tilting said steering roll about the second axis, to return the belt to the predetermined path;
• and
• means for compensating for backlash in said tilting means so that oscillation of the belt about the predetermined path is minimized, wherein said compensating means includes a device which performs the routine of tilting said steering roll in a first direction and then incrementally tilting said steering roll in a second direction, opposite the first direction, to determine a responsiveness of said tilting means.