Abstract: A label printing apparatus includes a main frame, a drum housing privotably mounted in the main frame, and a printing drum, mounted in the drum housing, which comprises a plurality of discs each having a series of die groupings about its periphery as well as a groove associated with each die grouping. An assembly for setting each disc to place a selected die grouping in printing position and for simultaneously shifting all of the discs to shift each set die grouping from a first to a second character printing position comprises a spur gear mounted for reciprocation in the direction of the printing drum axis and for rotation to selectively engage each disc and to disengage from all discs. A locking bar, having a notch, is linked to the spur gear to reciprocate with it and position the notch in alignment with the disc engaged by the spur gear. The remainder of the bar projects into a groove in each of all other discs to hold them against rotation during the setting operation.

Abstract: A label printing apparatus includes a main frame, a drum housing pivotably mounted in the main frame, and a printing drum, mounted in the drum housing, which comprises a plurality of discs each having a series of die groupings about its periphery as well as a groove associated with each die grouping. An assembly for setting each disc to place a selected die grouping in printing position and for simultaneously shifting all of the discs to shift each set die grouping from a first to a second character printing position comprises a spur gear mounted for reciprocation in the direction of the printing drum axis and for rotation to selectively engage each disc and to disengage from all discs. A locking bar, having a notch, is linked to the spur gear to reciprocate with it and position the notch in alignment with the disc engaged by the spur gear. The remainder of the bar projects into a groove in each of all other discs to hold them against rotation during the setting operation.

Abstract: A snap-action fastener assembly is disclosed, which provides ease of assembly and disassembly of a print disc to and from a serial printer. The snap-action fastener assembly comprises a necked shaft connected to the serial printer, and a pair of flexing jaws connected to the print disc. When pressure is applied about the jaws, they are caused to widen so as to easily slip over the shaft. When the pressure is released, the jaws snap back to a locked position. When the jaws are positioned about the necked section of the shaft in a pressure released condition, the print disc will be securely locked upon the shaft.