Abstract: The present invention relates generally to a printing system, and more specifically to an ordering of color-forming layers in a direct thermal printing medium. The present invention provides a direct thermal print medium with an ordering of the color layers that improves the perceived image sharpness and color uniformity of prints.

Abstract: The present invention relates generally to a printing system, and more specifically to an ordering of color-forming layers in a direct thermal printing medium. The present invention provides a direct thermal print medium with an ordering of the color layers that improves the perceived image sharpness and color uniformity of prints.

Abstract: A method and apparatus for expanding a color gamut of a direct thermal printer is described. The method includes, in a three-color direct thermal printer having at least a print head, the print head including print head elements, dynamically adjusting a duty cycle of at least one of the colors depending on the color to be printed in each pixel of an image.

Abstract: A method and apparatus for expanding a color gamut of a direct thermal printer is described. The method includes, in a three-color direct thermal printer having at least a print head, the print head including print head elements, dynamically adjusting a duty cycle of at least one of the colors depending on the color to be printed in each pixel of an image.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: In one aspect of the invention there is disclosed a multicolor thermal imaging system wherein different heating elements on a thermal print head can print on different color-forming layers of a multicolor thermal imaging member in a single pass. The line-printing time is divided into segments, each of which is divided into a plurality of subintervals. All of the pulses within the segments have the same energy. In one embodiment, every pulse has the same amplitude and duration. Different colors are selected for printing during the different segments by varying the fraction of subintervals that contain pulses. This technique allows multiple colors to be printed using a thermal print head with a single strobe signal line. Pulsing patterns may be chosen to reduce the coincidence of pulses provided to multiple print head elements, thereby reducing the peak power requirements of the print head.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A model of a thermal print head is provided that models the thermal response of thermal print head elements to the provision of energy to the print head elements over time. The amount of energy to provide to each of the print head elements during a print head cycle to produce a spot having the desired density is calculated based on: (1) the desired density to be produced by the print head element during the print head cycle, (2) the predicted temperature of the print head element at the beginning of the print head cycle, (3) the ambient printer temperature at the beginning of the print head cycle, and (4) the ambient relative humidity.

Abstract: A multicolor direct thermal imaging method and an imaging member for use therein, wherein a multicolor image is formed in a thermal imaging member having at least two different image-forming compositions capable of forming two different colors. Heat is used to form an image in the first color at a first speed of travel of the thermal imaging member with respect to the source of heat, and heat is used to form an image in the second color at a second speed of travel of the thermal imaging member with respect to the source of heat, where the first speed of travel and the second speed of travel are different from each other.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A method for controlling the print density of individual heating elements of a thermal print head array determines respective energy values for each heating element in response to image pixel data to be printed, multiplies determined energy values by a respective predetermined correction factor for one or more respective heating elements for improving print density consistency between individual heating elements, and dithers adjusted energy values from the step of multiplying as a function of adjacent image pixels.

Abstract: A thermal printer is disclosed which includes a plurality of thermal print heads, each of the plurality of thermal print heads being operable to print a distinct one of a plurality of colors. The plurality of thermal print heads may print output at a plurality of spatial resolutions. The thermal printer may include dot size varying means for varying perceived levels of color printed by the thermal printer by varying sizes of dots printed by the plurality of thermal print heads. The printer may perform various image processing steps on an image to be printed, such as tone scale adjustment, thermal history control, and common mode voltage correction, to improve the perceived quality of the printed image. The thermal printer may be incorporated into a digital photo-printing vending machine for printing images provided by a customer.

Abstract: Described herein are methods, devices and reagents for direct thermal imaging and, more particularly, for multicolor direct thermal imaging, wherein a direct thermal imaging member comprising different image-forming compositions is imaged at different speeds by a source of heat to form a multicolored image.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A multicolor direct thermal imaging method wherein a multicolor image is formed in a thermal imaging member comprising at least first and second different image-forming compositions and a thermal printer for use in practicing the method. Heat is applied to at least the second image-forming composition while the first image-forming composition is at a first baseline temperature (T1) to form an image in at least the second image-forming composition, and heat is applied to at least the first image-forming composition while it is at a second baseline temperature (T2) to form an image in at least the first image-forming composition, wherein T1 is different from T2.

Abstract: A method for controlling the print density of individual heating elements of a thermal print head array determines respective energy values for each heating element in response to image pixel data to be printed, multiplies determined energy values by a respective predetermined correction factor for one or more respective heating elements for improving print density consistency between individual heating elements, and dithers adjusted energy values from the step of multiplying as a function of adjacent image pixels.

Abstract: Techniques are disclosed for performing thermal history control in a thermal printer in which a single thermal print head prints sequentially on multiple color-forming layers in a single pass. Each pixel-printing interval may be divided into subintervals, which may be of unequal duration. Each sub-interval may be used to print a different color. The manner in which the input energy to be provided to each print head element is selected may be varied for each of the subintervals. For example, although a single thermal model may be used to predict the temperature of the print head elements in each of the subintervals, different parameters may be used in the different subintervals. Similarly, different energy computation functions may be used to compute the energy to be provided to the print head in each of the subintervals based on the predicted print head temperature.