Ribbon cassette

Claim 1

A film ribbon cassette for a printer comprising: (a) a casing having first, second, and third generally parallel spaced-apart non-rotating walls defining a first tape supply compartment and a second spent tape compartment; (b) apertures in said first, second and third walls; (c) a fixed hollow bearing extending orthogonally from said second wall into said first compartment and having its central axis aligned with the center of said apertures; (d) a tape supply spool having an aperture sized to ride upon said fixed bearing; (e) a shaft extending from said first compartment within said first bearing through said second compartment, through said aperture in said third wall and outside said cassette, providing a manual advancing knob outside the cassette; (f) a takeup drive roller concentrically affixed to said shaft and located in said second compartment; (g) a pinch roller having an axis of rotation parallel to said drive roller and cooperating with said drive roller to feed the ribbon; (h) means for guiding ribbon from said supply spool outside of said first compartment and into said second compartment and between said rollers; (i) driving engagement means formed at the end of said shaft within said fixed bearing for receiving and engaging a rotary drive outside said cassette which in turn drive said rollers and advance the ribbon; (j) a pair of strippers, attached to said cassette at one end and engaging said rollers at their other ends for disengaging spent ribbon from said rollers; and (k) a ribbon supply sensor and spool engaging member which serves as a means to apply drag to said supply spool, said sensor including a generally semicircular member having an inner concave arcuate surface which directly engages an arc formed on the outer peripheral surface of said ribbon supply spool, said member being affixed at one end to said cassette and including means for biasing said member against said supply spool to provide drag opposing rotation thereof.