Abstract: The present invention is a method and apparatus for communicating to a printer a type of installed printer cartridge, where the combination of the cartridge and the printer form a magnetic coupling that can generate a cartridge specific code to identify the toner cartridge as being of a predetermined type. In a preferred embodiment, the magnetic coupling is achieved using at least two reed switches preferably mounted on the printer, with the reed switches biased using fixed magnetic elements placed immediately adjacent the reed switches. In the absence of any further magnetic fields, the reed switches are selected to provide a known set of switch positions corresponding to a bit value of one (“1”) for an open circuit and a bit value of zero (“0”) for a closed circuit.

Abstract: An apparatus for communicating to a printer a type of installed printer cartridge, where the combination of the cartridge and the printer form a magnetic coupling that can generate a cartridge specific code to identify the toner cartridge as being of a predetermined type. In a preferred embodiment, the magnetic coupling is achieved using at least two reed switches preferably mounted on the printer, with the reed switches biased using fixed magnetic elements placed immediately adjacent the reed switches. In the absence of any further magnetic fields, the reed switches are selected to provide a known set of switch positions corresponding to a bit value of one (“1”) for an open circuit and a bit value of zero (“0”) for a closed circuit.

Abstract: In medium to high volume printers using more than one print head, multiple documents may be printed side by side in one pass. Multiple rolls of ribbon are utilized on the ribbon mandril to accommodate the documents. The ribbon is kept taut across its print head by the feed system controller. When the outside diameters of the two rolls of ribbon vary, the system keeps one ribbon taut and the other tends to go slack at the print head. A split sleeve mandril with a differential mechanism connecting the two sleeves of the mandril assures that both ribbons are maintained taut. The preferred differential mechanism may be a planetary gear arrangement, or a thrust bearing arrangement. A unique ribbon roll holding mechanism, to hold the ribbon roll at the selected place on the mandril is also provided.

Abstract: An apparatus for communicating to a printer a type of installed printer cartridge, where the combination of the cartridge and the printer form a magnetic coupling that can generate a cartridge specific code to identify the toner cartridge as being of a predetermined type. In a preferred embodiment, the magnetic coupling is achieved using at least two reed switches preferably mounted on the printer, with the reed switches biased using fixed magnetic elements placed immediately adjacent the reed switches. In the absence of any further magnetic fields, the reed switches are selected to provide a known set of switch positions corresponding to a bit value of one (“1”) for an open circuit and a bit value of zero (“0”) for a closed circuit.