Abstract: A noncontact seal for a donor roll in an electrophotographic printing machine. The seal is fixed in the developer housing and envelopes each end of the donor roll but does not contact the donor roll. The small space does not allow a positive airflow sufficient to cause toner particles to be emited from the developer housing so as to contaminate the other portions of the printing machine. The seal is made of a low friction material such as DELRIN.RTM. so that toner particles do not stick to the seal and cause a buildup that would be detrimental to the photoreceptive member.

Abstract: A developer backer bar having a substantially flat surface for interfacing with a noncontact developer member. The backer bar is arranged so that it can be retracted for clearance purposes when removing or inserting a xerographic CRU. Upon installation of the CRU, the backer bar is biased into position to maintain a development zone within predetermined parameters. The substantially flat surface eliminates or minimizes errors that may result from slight variations in axial alignment between the backer bar and the developer member.

Abstract: A channel for recirculating a stream of air located adjacent a stream of marking particles exiting substantially tangentially from a marking particle transport member within a developer unit is provided. The stream of marking particles defines an inner boundary thereof extending tangentially from a first position adjacent to the transport member and defines an outer boundary thereof spaced from the transport member and the inner boundary. The channel includes a first member positioned outside the stream of marking particles. At least a portion of the first member is positioned substantially adjacent the outer boundary of the stream of marking particles and is spaced from the transport member. The channel also includes a second member connected to the first member and a third member connected to the second member. The second member is positioned adjacent the transport member and is spaced from the stream of marking particles.

Abstract: An apparatus for removing magnetic carrier beads and similar particles from a photoconductive surface includes a magnetic roller for magnetically attracting and removing the beads from the photoconductive surface. A housing has at least one v-shaped support, and the housing contains the magnetic roller. A back-up shaft is disposed on a side of the photoconductive surface opposite the housing and is supported by the v-shaped support. The shaft and the magnetic roller form a uniform gap having a width of 0.65 +/-0.10 mm.

Abstract: An apparatus for enhancing contact between a copy sheet and a developed image positioned on a photoconductive member includes a cam movable between a first position and a second position. The apparatus further includes a mechanism for moving the cam between its first position and its second position. Additionally, the apparatus includes a contact member being spaced apart from the copy sheet in a first mode of operation and being in contact with the copy sheet in a second mode of operation. Moreover, the apparatus includes a mechanism for positioning the contact member in its first mode of operation in response to the cam being moved to its first position, and in its second mode of operation in response to the cam being moved to its second position.

Abstract: A transfer blade apparatus for ironing a sheet against the photoreceptor belt during transfer, and smoothing out deformities which cause deletions is disclosed. The transfer blades include a flexible tip to absorb the impact of the blade as it contacts paper, and a spring load to limit and control the force applied to the sheet. Sensors are also utilized to monitor and adjust the timing of the blades.

Abstract: A sheet transport system having a sheet release mechanism to effect release of a sheet from the sheet transport system at a point near the end of the transfer process. The sheet release mechanism includes a member positionable at a first fixed position spaced apart from the path of the sheet and a second fixed position within the path of the sheet. The sheet release mechanism is located on the side of the sheet opposite the side to which the toner image is transferred.

Abstract: A dual mode raster input scanner to scan either or both sides of a moving document advancing along a paper path through a scanning station in a first mode, and to scan one side of a stationary document on a scanning platen in a second mode. A scanning station, for scanning in a first mode, includes two scanning elements supported closely adjacent each other and on either side of the document path for scanning substantially simultaneously both sides of a document. A scanning platen supports a document for scanning in a second mode. One of the scanning elements is supported in a scanning position closely adjacent the other scanning element during said first mode and for scanning movement past said scanning platen in said second mode. A single sheet document input is also provided for the supply of single sheets or computer fanfold webs.