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US 5,993,092 AGranted
Printer with reversible ribbon driving means for rewinding overshot ribbon
AssigneeITW Limited
InventorAnthony James Palmer
Life of this patent
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AssigneeITW Limited
InventorAnthony James Palmer
Estimating the term…
A thermal printer for printing on a continuous print medium by ink transfer from a thermal print ribbon has a print head which is pivotally mounted and which is driven in an oscillatory nodding motion by means of a stepper motor so as repeatedly to bring a linear array of energizable printing elements to bear against a platen roller. Both the element array and the platen extend transversely to respective paths of travel of the print medium and the ribbon. The print medium is fed through the printer from an inlet region, between the platen and print head, and thence to an outlet region. The instantaneous rate of travel of the print medium past the print head is substantially the same as the rate of feed of print medium to the printer. Typically this rate is of the order of 250 to 400 mm per second. The ribbon also travels between the print head and the platen, overlying the print medium and is driven in such a manner that it travels at the same rate as the print medium during each printing operation. Between each printing operation the ribbon is driven in reverse to rewind any unused portion of ribbon which has overshot the printhead.
A thermal printer for printing on a continuous print medium by ink transfer from a thermal print ribbon, comprising a print medium path structure between inlet and outlet regions of the printer, a platen extending transversely of said path, a thermal print head having energisable print elements and located in an opposing relationship with respect to the platen on the other side of the print medium path structure from the platen, a ribbon path structure which, between the print head and the platen, runs in the same direction as and lies adjacent the print medium path, a processor operable to bring the print head and the platen together in successive printing operations respectively achieved with successively adjacent areas of said ribbon, and a ribbon drive operable to drive the ribbon along the ribbon path in a first direction at variable rates during the printing operations, and being controlled by said processor to drive said ribbon between said successive printing operations in a second direction opposite to the first direction, wherein the ribbon drive is controlled by the processor to vary the length of ribbon driven in the second direction as a function of the speed of ribbon driving in the first direction.
A method of printing on a continuous print medium, comprising providing a printer having a print head with energisable print elements, and a platen, the print head and the platen being located in an opposing relationship with respect to each other, feeding the print medium to the printer at a continuous feed rate and passing it between the print head and the platen in the same direction as and adjacent the print medium, feeding a print ribbon between the print head and the platen, and periodically bringing the print head and the platen together and energising the print elements with the ribbon in contact with the print medium to cause transfer of ink from the ribbon to the print medium in a printing operation, wherein the print medium is passed between the print head and the platen at a rate corresponding to the rate at which the print medium is fed to the printer during and between successive printing operations wherein, during each printing operation, the ribbon is passed in a first direction between the print head and the platen in contact with the print medium, the rate at which the ribbon moves during the printing operation being variable in response to the rate of travel of the print medium in the printer and wherein the ribbon is moved in a second direction which is the reverse of the first direction, between printing operations;
A printer for printing on a continuous print medium by ink transfer from a print ribbon, comprising a print medium path structure, a platen extending transversely of the path, a print head having energisable print elements and located in an opposing relationship with the platen on the other side of the print medium path from the platen, a ribbon path structure which, between the print head and the platen, runs parallel with and lies adjacent the print medium path, a ribbon take-off spool, a ribbon take-up spool which is belt driven with a belt via a slipping clutch drive, a reversible ribbon drive and a printing actuator operable to bring the print head and the platen together in successive printing operations, said reversible ribbon drive being reversible in incremental amounts corresponding to a distance in which the ribbon overshoots the print head between said successive printing operations.
Dependencies are inferred from the claim text.