Thermal printer
AssigneeSanders Associates, Inc.
InventorsDean-Yuan Liu, Jon S. Guy, Howard W. H. Siu, Michael A. Shaver
Life of this patent
Estimating the term…
Abstract
A thermal printer of the three-pass variety for printing in color featuring a sheet feeder, automatic registration, and ejection of the sheet when printing is complete. A rotatable, cylindrical drum has the print head close adjacent thereto and includes a releasable clamp for receiving the paper from the sheet feeder. The paper is clamped to the drum and the drum rotated past the print head three times, one for each color. The drum is then rotated to release and eject the paper. Sensors are provided to detect and monitor the position of the drum during its printing operation and to monitor the status of the paper supplied to the clamping mechanism.
Claims7
In a thermal printer having a thermal print head for selectively generating points of heat traversely across a print path and a driven ribbon having a transferable print medium thereon transported through the space between the print head and a sheet of print receiving media, the improved print media and ribbon drive comprising:
- (a) a horizontally disposed rotatable cylindrical drum having the print head in close adjacent parallel-spaced relationship to said drum's outer surface and the ribbon passing between the print head and said outer surface;
- (b) releasable clamping means for clamping the edge of a sheet of receiving media to said surface;
- (c) drive means for rotating said drum in a first direction being the printing direction and in a second direction, opposite said first direction, being the release direction and for stopping said drum and at first point with said clamping means adjacent the print head when said drum is rotating in said printing direction being the top of sheet point and at a second point with said clamping means adjacent the lowest point of said drum's rotational path when said drum is rotating is said release direction being the release point;
- (d) clamp release means carried by said drum and operably connected to said drive means for releasing said clamp means only as said drum is being stopped at said release point when rotating in said release direction;
- (e) first guide means for directing a sheet of receiving media onto said suface with its leading edge disposed in said released clamping means when said drum is stopped at said release point;
- (f) second guide means for receiving and guiding a sheet of receiving media off of said surface when said drum is rotated between said top of sheet point and said release point in said release direction and said clamping means is released;
- and,
- (g) control means connected to said drive means and the driven ribbon for rotating said drum in said print direction to clamp a sheet of receiving media, rotating said drum in said print direction to said top of sheet position, positioning the ribbon at the top of its first color, step rotating said drum in said print direction and stepping the ribbon in synchronization therewith while printing the first color line by line, positioning the ribbon at the top of its second color, step rotating said drum in said print direction and stepping the ribbon in synchronization therewith while printing the second color line by line, positioning the ribbon at the top of its third color, step rotating said drum in said print direction and stepping the ribbon in synchronization therewith while printing the third color line by line, and rotating said drum in said release direction to said release position to unclamp and eject the printed receiving media.
Dependencies are inferred from the claim text.