Abstract: A multicolor imaging system is described wherein at least two, and preferably three, different image-forming layers of a thermal imaging member are addressed at least partially independently by a thermal printhead or printheads from the same surface of the imaging member by controlling the temperature of the thermal printhead(s) and the time thermal energy is applied to the image-forming layers. Each color of the thermal imaging member can be printed alone or in selectable proportion to the other color(s). Novel thermal imaging members are also described.

Abstract: A multicolor imaging system is described wherein at least two, and preferably three, different image-forming layers of a thermal imaging member are addressed at least partially independently by a thermal printhead or printheads from the same surface of the imaging member by controlling the temperature of the thermal printhead(s) and the time thermal energy is applied to the image-forming layers. Each color of the thermal imaging member can be printed alone or in selectable proportion to the other color(s). Novel thermal imaging members are also described.

Abstract: Techniques are disclosed for stitching images printed by a multi-head printer in a manner that is relatively insensitive to misregistration of the image segments. When a pair of overlapping print heads print a pair of adjacent image segments which meet in a stitching region, printing at each location in the stitching region is accomplished by both print heads with a weighting that depends on the location being printed within the stitching region. In one embodiment, for example, the output of each print head is weighted by a linear function of horizontal pixel position. Techniques are also disclosed for selecting screening patterns for use when stitching is performed with variable-dot printers. Such screening patterns are selected to minimize variations in density that may arise as the result of cross-web and/or down-web misregistration.

Abstract: There is described a nanoporous receiver element for use in thermal mass transfer imaging applications. The receiver element comprises a substrate carrying an image-receiving layer comprising particulate material and a binder material. The substrate may comprise a material having a compressibility of at least 1% under a pressure of 1 Newton per mm2 (1 MPa). Optionally, there may be provided, between the substrate and the nanoporous receiving layer, a layer having a thickness of less than about 50 &mgr;m which is comprised entirely of a material having a compressibility of less than about 1% under a pressure of 1 MPa. Alternatively, the substrate may comprise only the material having a compressibility of less than about 1% under a pressure of 1 MPa, provided that the thickness of the substrate does not exceed about 50 &mgr;m.

Abstract: A technique for optimizing or enhancing color images. Embodiments are disclosed for creating an enhanced color image, including the enhancement of perceived color uniformity. In a “dot-on-dot” registration scheme for producing color images, the dots need to be precisely superimposed on each other to provide optimum or enhanced images. The dot-on-dot registration produced by a single head thermal printer is generally acceptable, but a single head machine is very slow because multiple passes (reciprocation) are required to lay down multiple colors of dots. In a much faster multi-head or tandem thermal imaging system a serious problem of dot misalignment may cause moire patterns or other visual artifacts in the color images produced by dot patterns. A solution to this problem is disclosed herein which intentionally misregisters superimposed dots in a novel and particular manner to achieve image optimization.

Abstract: A multicolor imaging system is described wherein at least two, and preferably three, different image-forming layers of a thermal imaging member are addressed at least partially independently by a thermal printhead or printheads from the same surface of the imaging member by controlling the temperature of the thermal printhead(s) and the time thermal energy is applied to the image-forming layers. Each color of the thermal imaging member can be printed alone or in selectable proportion to the other color(s). Novel thermal imaging members are also described.

Abstract: There is described a nanoporous receiver element for use in thermal mass transfer imaging applications. The receiver element comprises a substrate carrying an image-receiving layer comprising particulate material and a binder material. The substrate may comprise a material having a compressibility of at least 1% under a pressure of 1 Newton per mm2 (1 MPa). Optionally, there may be provided, between the substrate and the nanoporous receiving layer, a layer having a thickness of less than about 50 &mgr;m which is comprised entirely of a material having a compressibility of less than about 1% under a pressure of 1 MPa. Alternatively, the substrate may comprise only the material having a compressibility of less than about 1% under a pressure of 1 MPa, provided that the thickness of the substrate does not exceed about 50 &mgr;m.

Abstract: There is described a thermal recording system which utilizes a donor element comprising a substrate and a thermal transfer material layer having a dye-containing phase which is amorphous and wherein the dye or dyes present in the amorphous phase form a continuous film. Imagewise heating of the medium transfers portions of the transfer layer to a receiver sheet, thus forming an image. The transfer layer may also include a non-dye phase comprising a thermal solvent. During the heating of the donor element, the crystalline thermal solvent melts and dissolves or liquefies at least a portion of the dye-containing phase, thereby lowering the temperature at which transfer of the transfer layer occurs.

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 thermal print head model generates predictions of the temperature of each of the thermal print head elements at the beginning of each print head cycle based on: (1) the current ambient temperature of the thermal print head, (2) the thermal history of the print head, and (3) the energy history of the print head. 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, and (2) the predicted temperature of the print head element at the beginning of the print head cycle.

Abstract: We disclose an electronic imaging method and apparatus capable of effectively and accurately sensing and interpolating color image data received from a two-dimensional array of discrete image sensing elements, particularly, from a so-called “Bayer Pattern” array. In operation, the method and apparatus both extract one-color image data from the two-dimensional array and generate therefrom fully color-recovered image data by a combination of interpolation and non-linear filtering. Efficiency is accomplished, without departure from good accuracy, by performing two one-dimensional color recovery applications and essentially incrementally combining the results thereof. The first one-dimensional color recovery application generates a partially color-recovered image in which, for each row in that dimension, values are recovered for all of the colors present in that row.

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: There is described a thermal recording system which utilizes a donor element comprising a substrate and a thermal transfer material layer having a dye-containing phase which is amorphous and wherein the dye or dyes present in the amorphous phase form a continuous film. Imagewise heating of the medium transfers portions of the transfer layer to a receiver sheet, thus forming an image. The transfer layer may also include a non-dye phase comprising a thermal solvent. During the heating of the donor element, the crystalline thermal solvent melts and dissolves or liquefies at least a portion of the dye-containing phase, thereby lowering the temperature at which transfer of the transfer layer occurs.

Abstract: There is disclosed a scanning beam position indicating arrangement which is employed in an electronic printer for accurately clocking a writing beam of the printer as a function of writing beam position. One embodiment of a scanning beam position indicator arrangement utilizes a Fresnel mirror device. Another embodiment utilizes a holographic encoding element. Still another embodiment utilizes a ellipsoidal mirror device. Another embodiment utilizes a holographic lens.

Abstract: A low noise avalanche photodetector (APD) having repeated superlattice units. Where the principal ionizing carriers are electrons, each unit is formed from p.sup.+ -n.sup.+ layers of a first material, a near intrinsic layer of the first material, and a near intrinsic layer of a second material having an ionization threshold which is larger than that of the first material. Such an APD can be fabricated in a GaAs/AlGaAs material system.

Abstract: An automatic focusing system for a camera apparatus utilizes a two-dimensional photosensitive array to determine image sharpness as a function of the image information sensed in both the rows and columns of individual photosensitive pixel elements. A transfer function may be imposed upon the electronic information signal derived from the two-dimensional photoresponsive array or, alternatively, upon the incident scene light to the two-dimensional photoresponsive array to centerweight the focus condition determining signal where the principle subject will be most likely framed.