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: A corona generating device together with a coronode wire end block assembly is described, wherein the end block includes a spring member adapted for connection to a coronode wire which operates as a circuit breaker at the contact point of the end block thereby terminating the power supply, and preventing a potentially dangerous and destructive arcing situation in the event the wire ruptures. In a preferred embodiment the end block assembly comprises a conductive electrode having at one end a coronode contact and, at the other end a conductive plug adapted for engagement with a power supply contact, with the electrode being positioned in an electrically insulating holder between the coronode contact and the conductive plug. The conductive spring is mounted to the electrically insulating holder on one side of the coronode contact with the other end of the conductive spring being connected to the coronode wire.