Abstract: Customer billing system for electrostatographic reproducing machines in which a replaceable copy cartridge provides a guaranteed number of copies or prints, each cartridge having an integral copy counter which, on reaching a predetermined copy count, is disabled, rendering the cartridge dead and activating an additional copy counting mechanism for counting a limited number of grace copies that can be made using the dead cartridge, after which further operation of the machine is prevented until a new cartridge is installed.

Abstract: An imaging process having reduced toner contamination of the printing machine and copies produced therefrom is provided where successive developed toner images are formed on successive registered areas of an endless imaging member movable through a path past a plurality of processing stations by creating an electrostatic fringe field across the width of the imaging member in advance of the lead edge of developed toner image in a registered area of the image member of sufficient magnitude to attract otherwise contaminating toner thereto as it traverses the path whereby contaminating toner is not attracted to successive registered areas of the imaging member. In a preferred embodiment the fringe scavenger filed has a gradient more than 15 volts per millimeter.

Abstract: An apparatus and method for developing an electrostatic latent image on an imaging member wherein a development nip is formed between a rotatably mounted cylindrical developer roll and the imaging member. The nip is initially supplied with a wedge shaped layer of developer material to develop the electrostatic latent image on the imaging member. Periodically at stated intervals the developer material is collected from the developer roll and development nip and the same measured amount of developer material is resupplied to the development nip.

Abstract: A toner dispenser having a rotatable cylindrical dispenser roll and an automatic low toner level indicator comprising a lamp and photocell mounted in opposed walls of the dispenser adjacent the bottom of the dispenser housing. The lamp and photocell are separated from the toner in the dispenser by transparent windows. A wiping arrangement is provided inside the dispenser to periodically clean the windows including wiper pads biased into contact with the windows and movable periodically back and forth across the surface of the windows in response to rotation of the dispenser roll.

Abstract: In an electrostatographic copier in which imaging material is transferred from an image support surface to an overlying copy sheet in a transfer station, by electrical transfer charges, the variable leakage conduction of these transfer charges by the copy sheet away from the transfer area (to contacting conductive members) changes the available transfer field strength, thus affecting transfer efficiency and quality. Here the conductive members contacting the copy sheet while it is in the transfer station are electrically isolated from ground and connected to feed back the sheet leakage currents to circuitry providing a compensatory change in the applied transfer charges.

Abstract: Applicator structure for applying toner offset preventing liquid to a heated fuser roll structure for fusing toner images to copy sheets. The applicator structure comprises a wick member and support therefor wherein the support is characterized by having a plurality of concave surfaces each of which can cooperate with the fuser roll structure to retain a different portion of said wick member in engagement with said fuser roll structure. The support is adapted to be manually repositioned relative to the fuser roll so that each of the concave surfaces can be disposed opposite the fuser roll structure.

Abstract: An electrostatographic machine is provided with a manually operable switch for changing the output of a pre-transfer corona discharge device depending upon the contrast characteristic of an original document to be copied. If the pre-transfer device is energized by an A.C. signal biased to a preselected D.C. level, this D.C. bias level may be changed in accordance with contrast quality of the original document to vary the image density at which transition from transfer suppression to transfer enhancement takes place. Alternatively, the A.C. excitation level may be varied to change the point at which transition from transfer enhancement to transfer suppression occurs.