Abstract: A method is provided to increase the gray level resolution of a thermal print head. The thermal print head includes a plurality of heaters which are used to heat color dye so as to deposit the color dye on a paper to form a line image. The line image contains a plurality of pixels, each formed by one heater. When generating a pixel, a pulse sequence is fed to one heater to control the heater″s heating period. The pulse sequence contains first and second portions. The first portion contains a plurality of consecutive pulses which is used to generate a first gray level. And the second portion contains at least one empty pulse period followed by at least one pulse which is used to generate a second gray level. The combination of the first and second gray levels will determine the gray level of each pixel of the line image.

Abstract: A printing method for printing a pixel at a gray level x on paper by a printer. The printer includes a thermal print head, which includes a heater for heating a ribbon to print pixels from gray levels 1 to m−1 on the paper, and the ribbon. The method includes: if x is not greater than a value n, heating the ribbon x times and evenly distributing the heating initiation times of the x times between the time point 0 and the time point (m*(x−1)/n) for printing the pixel at gray level x on the paper. If x is greater than the value n, heating the ribbon x times and evenly distributing the heating initiation time of the n times between the time point 0 and the time point (m*(n−1)/n) and distributing the heating initiation times of the x−n times after the heating initiation time points of the n times.

Abstract: A color printer with a single photo sensor for detecting the position of the ink ribbon. A single photo sensor is place so that it can detect transparent and opaque sections of the ink ribbon. The ribbon winds at a constant speed, so the pattern of transparent and opaque sections periodically repeats. The controller can use the periodicity of the transparent and opaque sections to calculate which dye frame the print head is positioned over. Using this information, the printer can advance the ink ribbon to the desired dye frame for printing onto the photo paper.

Abstract: A method for recognizing a color of a printing ribbon includes providing a printing ribbon having a repeated sequence of dyed and undyed regions such that output of a photosensor sensing the ribbon is a low or high level based on a threshold. The method includes illuminating a sensing area of the ribbon, moving the ribbon relative to the sensing area, measuring output of the photosensor over time as the ribbon moves, correlating output of the photosensor to the repeated sequence as the ribbon moves to determine the color of the ribbon under the print head, and setting operational parameters of the printer and print head according to the color of the ribbon under the print head. The repeated sequence is unprintable black dye, yellow dye with undyed ribbon, magenta dye, undyed ribbon, cyan dye, and transparent overcoating with undyed ribbon.

Abstract: A method for generating a matte finish on a photo picture using a thermal printer includes using the thermal printhead to heat different areas of an overcoating dye frame of an ink ribbon by at least two distinct time periods to dispose overcoating on the photo picture. The two distinct time periods are a first time period and a second time period; the first time period disposing thicker layer of overcoating than the second time period. A matte finish pattern of overcoating comprises a two-dimensional array of cells wherein each cell is heated by either the first time period or the second time period based on a substantially random probability.

Abstract: A thermal printer includes a printer body, a thermal printhead installed in the printer body, a print ribbon installed in the printer body, and a control circuit for controlling the thermal printhead and the print ribbon. The print ribbon has regions of colored dye, regions of resistant overcoating, and regions of stampable overcoating capable of accepting an ink stamp. The print ribbon can be supplied as two exchangeable ribbons, one having colored dye and regions of resistant overcoating, the other having regions of stampable overcoating. The control circuit controls the thermal printhead and the print ribbon to print pictures having stampable images. An ink stamp can be externally applied to a stampable overcoating layer of the picture, an intermediate resistant overcoating layer protecting the image from damage.

Abstract: A integrated cartridge of a printer has a paper cassette for holding paper, and a two-reel ribbon cassette for positioning a printer ribbon, connected by a pair of braces. The ribbon cassette is rotatable, with respect to the paper cassette, or collapsible to make the integrated cartridge more compact for storage.

Abstract: A color printer includes an ink ribbon having a plurality of sequentially arranged dye regions, each of the dye regions having a plurality of dye frames for carrying dye of different colors, a ribbon driving device for causing the ink ribbon to move in a predetermined direction, a controller for controlling the color printer, and a plurality of optical detecting devices sequentially arranged and mounted adjacent to the ink ribbon. At least two output signals are detected when each of the optical detecting devices senses a dye frame, and each the output signal is defined as a phase. Position of the ink ribbon is discerned by the controller according to the phase and phase-to-phase variation recorded by the optical detecting devices when the controller commands the ribbon driving device to move the ink ribbon.