Unidirectional ribbon drive mechanism
AssigneeNCR Corporation
InventorsAlan H. Walker, Bradley W. Lewis, Thomas J. Bossack
Life of this patent
Estimating the term…
Abstract
A ribbon is driven past the printing station of a printer only when the print head is moved in the right-to-left direction across the printer. An endless timing belt causes rotation of a gear pulley that is in mesh with an idler gear. The idler gear is supported on a pair of projecting fingers of a plate that is swingable on the center of the gear pulley. The idler gear is responsive to the direction of rotation of the gear pulley through a drag effect of the projecting fingers with the bottom surface of the idler gear.
Claims20
Mechanism for driving a ribbon in a printer having a frame, said mechanism comprising an
- endless timing belt driven in reciprocating manner across said printer, a
- gear pulley engaged with said endless timing belt and rotatable about a pivot in either a clockwise or a counterclockwise direction in response to the direction of travel of said timing belt, an
- idler gear engaged with said gear pulley and operably associated in mesh relationship therewith, an
- idler gear support member swingable on said pivot and responsive to the direction of rotation of said gear pulley, said support member including projecting means engaging one surface of said idler gear to provide a drag effect thereon in opposition to rotation of said idler gear produced by rotation of said gear pulley, and a
- ribbon drive member comprising a drive gear in position to mesh with said idler gear and to drive said ribbon upon swinging of said idler gear in response to rotation of said gear pulley in one direction.
A printer having a frame and a print head movable in transverse direction,
- means for moving said print head in said direction, a
- ribbon cassette containing an endless ribbon operably associated with said print head, and
- means for advancing said ribbon past said print head during one direction of travel thereof, said ribbon advancing means comprising drive spindle means operably associated with said ribbon cassette, gear pulley means operably associated with said print head moving means, idler gear means operably associated with said gear pulley means and with said drive spindle means, and idler gear plate means engageable with said idler gear means and including projecting elements for effecting a drag on said idler gear means for swinging thereof into and out of mesh with said spindle gear means depending upon the direction of rotation of said gear pulley means.
In a printer having a frame, a print head movable in transverse manner across the printer, belt means for moving the print head in said manner, and a ribbon cassette positioned to provide a ribbon adjacent the print head for printing operation, the improvement comprising
- ribbon drive mechanism including drive gear means operably associated with said cassette for driving the ribbon past said print head, gear pulley means engaged with said belt means to be rotated thereby about a pivot in either a clockwise or a counterclockwise direction in response to the direction of movement of said print head, and idler gear means swingable about said pivot and responsive to the direction of rotation of said gear pulley means, said idler gear means being supported by projecting means on said gear pulley means effecting a drag on said idler gear means for swinging thereof into and out of engagement with said drive gear means.
Dependencies are inferred from the claim text.