Patent ID: 7484902
Filing Date: 2009-02-03
Classification: B41J

Abstract:
1. A ribbon cassette for a mailing machine, said cassette having laterally adjacent ribbon supply and ribbon take-up sides, and including: a housing comprised of an assembled base component and a mating cover component secured to one another and defining an interior space therewithin, said base component comprising a back wall, which faces rearwardly in the normal orientation of cassette operation, and said cover component comprising a front wall which faces forwardly in said normal orientation, one of said housing components including a peripheral wall extending about said housing and being comprised of an upper portion, a transversely spaced lower portion, and laterally spaced opposite end portions; said lower portion of said peripheral wall having an upwardly extending recess formed therein for receiving a print head assembly of a mailing machine, said recess being defined by an upper wall section and first and second lateral wall sections, said first and second lateral wall sections being spaced laterally with respect to one another and each having a lower edge; and said peripheral wall lower portion having an exit opening adjacent to and upstream of said first lateral wall section, taken with respect to the direction of ribbon travel from said supply side to said take-up side of said cassette, and having an entrance opening adjacent to and downstream of said second lateral wall section; a fresh ribbon supply spindle and a used ribbon take-up spindle rotatably mounted upon said base component within said interior housing space on said supply side and said take-up side of said cassette, respectively, each of said spindles comprising a circular base having an array of gear teeth extending about the circumference thereof, and a center shaft extending substantially normal to said base for supporting a roll of fresh or used printing ribbon thereon, respectively; an anti-reverse spring mounted upon said housing and having an outer end portion in engagement with said gear teeth of said take-up spindle, said anti-reverse spring being so configured and disposed as to permit rotation of said take-up spindle in a forward, ribbon-winding direction of said take-up spindle while preventing rotation of said take-up spindle in the reverse, ribbon-unwinding direction thereof; a constant-tension drag arrangement comprised of a radially expansible stub axle projecting forwardly from said base component and having a bore extending thereinto from a free forward end thereof and on an axis substantially normal to said back wall, an expansion member projecting rearwardly from said cover component, substantially normal to said front wall, into said bore of said stub axle so as to cause said stub axle to be presented in an expanded state, and a gear having an axial aperture through which said stub axle extends to rotatably mount said gear thereon, said stub axle being positioned to dispose said gear in meshing engagement with said gear teeth of said supply spindle, said stub axle and gear aperture being so dimensioned and configured that, in said expanded state of said stub axle, a surface portion thereof frictionally engages the surface defining said gear aperture with a force that is sufficient to retard rotation of said gear and thereby to exert a significant drag force, of substantially constant magnitude, upon said supply spindle; a guide bar extending transversely of said interior space of said housing, substantially normal to said back wall and said front wall of said base and cover components, respectively, and near said entrance opening in said lower portion of said peripheral wall of said housing, said guide bar having a guide surface that is offset laterally from a spanning line between said lower edge of said second lateral wall section and said center shaft of said take-up spindle, said offset being to the side of said spanning line opposite to the side thereof on which said lower edge of said second wall section of said peripheral lower wall portion is disposed, said housing being devoid of any wall portion providing underlying support for a ribbon in an area between said lower edge of said second lateral wall section and said take-up spindle; and a roll of postage-printing ribbon supported on said supply spindle in fixed relationship thereto for unwinding during rotation thereof, said ribbon having an end portion attached to said take-up spindle and traveling along a path from said supply spindle, outwardly of said housing through said exit opening, over said lower edges of said first and second lateral wall sections to span said print head assembly-receiving recess, back into said housing through said entrance opening, about said guide surface of said guide bar, and to said take-up spindle for winding thereupon.