Tape cartridge with reduced tangential drive force

A belt-driven tape cartridge, comprising:

• an outer housing, the housing having a front wall with a drive opening for receiving an externally mounted drive roller of a tape drive;
• first and second tape spools rotatably mounted in the housing;
• a length of tape having a first end portion wound on the first tape spool and a second end portion wound on the second tape spool, whereby rotation of the tape spools in opposite directions transfers tape back and forth between the spools;
• at least three roller supporting pins rigidly mounted in the housing, including a first roller supporting pin located adjacent said drive opening;
• a belt driving roller rotatably mounted on said first roller supporting pin, said driving roller having a circumferential driving surface facing said drive opening for contact with a drive roller extending through said opening to rotate said driving roller;
• belt guide rollers respectively mounted on the other two roller supporting pins;
• an endless drive belt extending around said driving roller and guide rollers to contact said tape portions wound on each of the tape spools;
• said first roller supporting pin having a cylindrical outer surface with at least one recess extending at least over a portion of said surface facing said drive opening, said recess comprising means for reducing the bearing surface area between said roller and roller supporting pin, whereby the tangential drive force required to rotate said driving roller is reduced;
• and
• the recess extending only partially around the circumference of said cylindrical outer surface of said first roller supporting pin, said recess facing said drive opening and not extending to portions of said outer surface of said first supporting pin facing away from said drive opening.

A method for reducing the tangential drive force required to drive a tape in a belt-driven tape cartridge, comprising the steps of:

• forming at least one recess in an outer cylindrical surface of a driving roller supporting pin to extend over at least a portion of said pin facing a drive opening of the cartridge;
• providing a driving roller with a central opening for rotatable engagement over said driving roller supporting pin and an outer circumferential driving surface;
• assembling the driving roller and supporting pin in a tape cartridge with a drive belt extending around the driving roller to contact tape on tape spools also assembled in the cartridge, the driving roller facing said drive opening;
• extending a drive member of a tape drive through the drive opening to contact the circumferential driving surface of said driving roller;
• and
• actuating the drive member to rotate the driving roller on the supporting pin and drive tape back and forth between the tape spools;
• the recess being of predetermined dimensions sufficient to substantially reduce the tangential drive force needed to rotate the driving roller to drive tape at a predetermined tension between the spools.

A tape transport assembly, comprising:

• a tape cartridge housing having a front wall with a drive opening;
• first and second tape spools rotatably mounted in the housing;
• a length of tape having a first end portion wound on the first tape spool and a second end portion wound on the second tape spool, whereby rotation of the tape spools in opposite directions transfers tape back and forth between the spools;
• at least three roller supporting pins rigidly mounted in the housing, including a first roller supporting pin located adjacent said drive opening;
• a belt driving roller rotatably mounted on said first roller supporting pin, said driving roller having a circumferential driving surface facing said drive opening;
• belt guide rollers respectively mounted on the other two roller supporting pins;
• an endless drive belt extending around said driving roller and guide rollers to contact said tape portions wound on each of the tape spools;
• a drive roller extending through said drive opening to engage said circumferential driving surface and rotate said driving roller and drive tape back and forth between the spools;
• and
• said first roller supporting pin having a cylindrical outer surface with at least one recess extending only over a portion of said surface facing said drive opening, said recess comprising means for reducing the bearing surface area between said roller and roller supporting pin, whereby the tangential drive force required to rotate said driving roller is reduced.