Abstract: A floating feedhead having a variable sheetpath for an electrophotographic printing machine. A feeder for feeding sheets from the top of a stack to a processor for a printing machine is disclosed. The feedhead is of a standard retard feed type having either a nudger roll/feed roll or a feed belt in combination with a retard member to separate sheets. The feedhead is connected to the sheet delivery area of the machine by a variable length, variable speed sheetpath. The sheetpath has a drive member such as a drive nip in cooperation with the feedhead. When the sheetpath is at its longest the feedhead and variable drive member operate at a higher speed to deliver the sheets to the sheet intake area at a predetermined time interval. As sheets are fed and the sheetpath becomes shorter, the variable drive and feedhead slow to maintain proper sheet timing. The sheetpath may be of a telescopic baffle configuration or could alternatively be a variable speed vertical transport arrangement.

Abstract: A sheet feeding and separating apparatus for feeding sheets from a stack by exerting a drive force against the top sheet. The sheet is urged off the stack by a nudger roll toward a retard nip formed where a feed roll contacts a retard roll. The retard roll is movable relative to the feed roll, and thus is capable of producing drive forces of varying magnitude at the retard nip to propel a sheet toward the copying mechanism. A controller signals the nudger roll to urge a sheet off the stack and then monitors a sensor to determine whether the sheet passes through the retard nip. A misfeed condition occurs when the sensor fails to detect a sheet within a predetermined length of time. In response, the controller moves the retard roll toward the feed roll to increase the drive force exerted on the sheet. The retard roll is further adapted to detect the occurrence of a multifeed when multiple sheets contact the retard nip.

Abstract: An automatic recovery apparatus reduces the number of shut downs due to fuser misstrips in an electrophoto-graphic device. A fuser misstrip occurs if the lead edge of a copy sheet does not emerge from the fuser nip. The fuser roller and the photoreceptor drive roller are stopped. These rollers are driven in the reverse direction until the copy sheet is released from the fuser. The rollers are then driven in the forward direction so that the copy sheet is re-fused. This automatic recovery apparatus is used for a photoreceptor misstrip. If the copy sheet remains attached to the photoreceptor belt after passing the stripping zone, it will jam in the cleaner module. If a sensor detects the copy sheet is still attached to the belt after the stripping zone, then the photoreceptor belt is reversed and the stripping procedure is repeated.

Abstract: An adjustable nudger roll for use in a friction retard feeder includes multiple springs used in conjunction with the nudger roll in order to allow greater latitude for adjustment of the normal force of the nudger roll against a substrate stack and in order to reduce the incidence of misfeeds. This arrangement adjusts the normal force on substrates as the requirement of the feed force changes and thereby reduces misfeeds and multifeeds.

Abstract: A sheet path velocity profile signature analysis apparatus which utilizes output from various idler rolls throughout the machine paper path to detect abnormalities. The constantly monitored and instantaneous velocity readings are compared with a base line velocity signature established at the factory. If the constantly monitored velocity profile is not within the pre-established operating parameters as set at the factory, automatic machine adjustment procedures are initiated and/or automatic service alerts are issued. The ability to constantly monitor the velocity profile throughout the machine enables preventative maintenance to occur and worn drive rolls, idler rolls and other transport devices can be replaced before catastrophic failure.

Abstract: A method and apparatus for transverse registration of image exposures on photoreceptive belts subject to lateral deviation from linear travel in which targets, corresponding in location to the image areas to be exposed, are used for the detection of lateral belt displacement and to control the transverse location of exposure scan. The targets are of a pattern defining a reference line and a line inclined with respect to the direction of belt travel so that the duration of time between passage of the target lines with respect to a spacially fixed sensing axis will vary with lateral displacement of the belt. The targets may assume a variety of specific patterns and the invention is applicable to single and multi-pass image exposure systems as well as to both modulated laser and light emitting diode types of exposure devices.

Abstract: A magnetic clutch provides an adjustable slip torque. A housing, having an outer surface of a predetermined frictional coefficient, is disposed around a portion of a shaft, and is rotatable relative to the shaft An outer magnetic member is disposed on the inner surface of the housing, and an inner magnetic member is attached to the shaft and disposed within the housing. The slip torque is adjusted by varying the amount of surface area exposure between the inner magnetic member and the outer magnetic member.