A portable printing system is provided for printing an image, such as alphanumeric or symbol information on a moveable recording medium, such as a tape, a sheet or the like, by means of manual scanning of the recording medium relative to the printing system. The printing system comprises a hand-held printer unit including a print head having an array of printing elements in combination with an adjacently disposed drive roller both disposed in cooperative arrangement along one edge of the printer unit. The drive roller is coupled to an encoder inside the unit that generates timing pulses upon rotational movement of the drive roller which control the rate of printing at the printing head of the printer to synchronize printing with the rate of movement of the recording medium relative to the printer unit. The printer unit may be detachably mounted to a recording medium transport unit which includes a platen which is engaged by the drive roller and print head with a recording medium and ink ribbon disposed between the print head and the platen. Alternatively, the printer unit may be hand-held with the drive roller and print head in engagement with a flat recording medium, such as an ordinary paper sheet. In either case, the recording medium travels in a path substantially perpendicular to the array of printing elements on the print head. A combination of two tape recording mediums is also disclosed to provide means to protect the printed image from the possibility of smudges and smears or other image deterioration from occurring directly on the printed image.