| 摘要 |
A ribbon metering drive accurately advances ribbon in a ribbon cartridge. The drive includes the drive roller, driven by the printer, and an idler roller mounted adjacent the drive roller. The drive and idler rollers have roughened, typically serrated, drive surfaces. The idler roller is lightly biased against the drive roller. The ribbon is guided through the ribbon drive so that it contacts substantially more than half the roughened drive surface of the idler roller. The ribbon is pulled through the ribbon drive by the action of the idler and drive rollers at the nip and also by the frictional engagement of the ribbon contacting the roughened surface of the idler roller. The low biasing force on the idler roller reduces wear and creep in the components to provide accurate ribbon metering over a longer life than is available with prior art ribbon drives.
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