Abstract: Disclosed is an electrostatic printer having a rotatable drum with a photoreceptor belt mounted on the periphery. The photoreceptor belt is advanced past a cathode ray tube which forms an electrostatic image on its surface. A wiper brush is recessed within an opening extending transversely of the drum surface and is mounted for movement from the recessed position to a position in which it wipes the face of the cathode ray tube face as the drum is rotated. Also enclosed in conjunction with the wiper is a mechanism for periodically indexing the supply of photoreceptor web from a supply reel to a take-up reel both located interiorly of the drum. The photoreceptor is advanced by mechanism including planetary gearing.

Abstract: Apparatus for controlling the advancement of punch cards or like sheet material past a plurality of work stations such as may comprise a data recorder used in the preparation and processing of punch cards. Control means are provided to sense the nature of an operation being performed on a particular card as well as the presence of punch cards at other of the plural work stations comprising the system and in response thereto selectively energize the advancement mechanism such that each punch card processed through the system will be advanced at an optimum rate. In the event no punching or printing operation is to take place on the punch card the speed of the advancement mechanism is increased considerably in excess of that which would otherwise enable the advancement mechanism to be accurately stopped.