Contact cleaning roller oscillated by a barrel cam

Abstract

A contact cleaning roller (CCR) system includes a shell having an electrostatically active outer surface and being supported by a close-fitting rotatable shaft. The shaft within the shell is provided with a cam groove extending from a first axial location to a second axial location disposed 180.degree. from the first axial location, and then back to the first axial location. A cam follower attached to the inner surface of the shell rides in the cam groove, causing the shell to oscillate axially of the shaft at a frequency of oscillation which is the numerical difference between the rotational frequencies of the shell and shaft. In a preferred embodiment, the CCR shell is nipped against a backing roller, which may be an idle roller or a driven roller, the web passing therebetween in contact with the working surfaces of both rollers. Outboard of the working surfaces, the shaft of the backing roller has a first drive roller having a first diameter, and the shaft of the barrel cam has a second drive roller nipped against the first drive roller and having a second diameter slightly different from the first diameter. Thus, the CCR shell turns at a rotational frequency imposed by the linear velocity of the web whereas the CCR shaft turns at a different frequency as imposed by the relative diameters of the two speed-controlling drive surfaces, the frequency differential being equal to the oscillation frequency of the CCR shell along the barrel cam.