Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2001-08-22
2004-03-09
Nerbun, Peter (Department: 3765)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C008S149000, C068S20500R, C239S069000
Reexamination Certificate
active
06704610
ABSTRACT:
This disclosure relates to a computer-assisted process in which a designer may predict the appearance of a desired multi-colored pattern on a substrate that is generated using precisely delivered quantities of liquid colorants that are available in only a relatively few colors. Specifically, this disclosure relates to a process by which a designer, working with a computer-aided design system, can reproduce an arbitrarily colored image using a relatively small palette of colors through the use of dithering and can be provided with an image that accurately predicts the appearance of that image on a specific substrate. In other embodiments incorporating the process disclosed herein, specific actuation instructions for a specific dye injection machine capable of patterning a moving textile substrate may be generated.
BACKGROUND
As is well known in the field of computer graphics, images displayed on a computer cathode ray tube (“CRT”) or liquid crystal display (“LCD”) or similar device typically are composed of a set of hundreds of thousands of individually addressable pixels or picture elements, each of which may carry a color shade that is selected from, say, 256 shades in a system in which the color is specified in an eight-bit digital system, to over 16 million different shades in a 24-bit system. These shades are “constructed” by appropriate combinations of three “primary” color components—red, green, and blue—of the color space traditionally associated with such display devices. As a means of expanding the total number of colors that can be constructed from a given set of available “primary” colors, various techniques collectively known as “dithering” were developed to increase the apparent color range of the displayed image, although these techniques are generally not needed for systems using 16 or more bits.
In the field of computer graphics, dithering is a term that is used to refer to a class of computer software algorithms that simulate, for display or patterning purposes, a greater number of apparent colors than those actually present on the display or substrate. These algorithms use techniques that are somewhat similar to the halftone methods that are employed in the printing industry. In such methods, small areas or “dots” of the process colors (e.g., the colors of the different individual contrasting colorants or dyes available for use) are arranged in close proximity into groups. These “dots” are directly analogous to the “pixel” concept in computer graphics, and corresponding to the smallest area on the substrate in which a quantity of colorant can be precisely and reliably placed.
When viewed by the unaided eye at a distance such that the eye cannot resolve the individual component dots, the dot grouping takes on a color that is an apparent blend of the colors of the individual dots, and can cause the eye to perceive a color that is different from that of any of the individual dots comprising the dot grouping. In halftone and dithering methods, the size as well as the color of the individual dots may be varied to assist in achieving the desired colors. The techniques described herein, however, are applicable whether or not the dot size (or the total quantity of ink per pixel) is varied.
Consistent with the above, as used herein the term “pixel” shall refer to the smallest area or location in a pattern or on a substrate that can be individually addressable or assignable with a given color. Alternatively, if clear from the context, the term “pixel” shall refer to the smallest pattern element necessary to define the line elements of the pattern to a predetermined level of detail, analogous to the pixel counts in imaging device resolution specifications (e.g., 1280×1024).
The techniques described herein are applicable to the patterning of a variety of substrates, but will be described in terms of an absorbent substrate such as a textile substrate. Dye application techniques that may be considered include, but are not limited to, silk screen printing, offset printing, and various methods in which a stream of dye is directed onto the substrate surface. While the techniques described herein can be used in conjunction with a variety of printing systems, they are particularly well suited to systems in which the dyed image is formed by the precise delivery of an individually specified aliquot of liquid dye to a predetermined location (i.e., the pixel to be colored) on the substrate surface. One such technique for use in patterning textile substrates is described, for example, in commonly-assigned U.S. Pat. Nos. 4,033,154; 4,116,626; 4,545,086; 4,984,169; and 5,195,043, all of which are hereby incorporated by reference herein. It should be understood that other textile substrates, such as decorative or upholstery fabrics, or other absorbent substrates, may also be used.
Machines embodying the patterning techniques described in the above-listed patent documents are particularly well-adapted for patterning textile substrates. Such machines consist fundamentally of a plurality of fixed arrays of individually controllable dye jets, each array being supplied by a respective liquid dye supply system carrying liquid dye of a specified color (known as a “process” color). Because the jets on each array are capable only of dispensing the liquid dye supplied to that array, the maximum number of different colors that can be directly applied to the substrate by the machine (i.e., the maximum number of process colors) equals the number of arrays. As will be explained below, the number of colors generated on the substrate may be much greater through in situ blending techniques, and the number of colors perceived to be on the substrate might be much greater still, through the use of the dithering techniques disclosed herein.
The arrays are positioned in parallel relationship, spanning the width of the substrate to be patterned (i.e., generally perpendicular to the direction of web travel). While the substrate moves along the path, it passes under each of the arrays in turn and receives, at predetermined locations on the substrate surface (i.e., at the pixel locations specified by the pattern data), a carefully metered quantity of dye from one or more of the dye jets spaced along the array. The control system associated with the machine provides for the capability of delivering a precise quantity of dye (which quantity may be varied in accordance with the desired pattern) at each specified location on the substrate as the substrate moves under each respective array, in accordance with electronically defined pattern information. An important feature of this system is that a given pixel on the substrate may receive liquid dye from several different arrays, thereby providing for the in situ blending of different dyes on the substrate within the same pixel, resulting in the generation of colors visually distinct from the inherent colors of the individually applied liquid dyes. It should be noted that the sequential nature of this process, with the second colorant being applied after—and therefore on top of—the first colorant, greatly complicates the task of predicting with accuracy the color of the resulting blend of colorants. Making such predictions is essential if the blended color is to be used with confidence in a dithering algorithm for the purpose of reproducing pattern colors accurately.
It should be understood that the techniques described herein are not limited to the specific patterning systems described above. For example, an arrangement of liquid colorant (e.g., dye) applicators, perhaps grouped in terms of color to be applied, may be traversed across the path of a sequentially indexed substrate while dispensing measured quantities of dye. Although such arrangement is distinct from the fixed array systems discussed above, it is believed that the teachings herein are fully applicable to and adaptable for use with such systems, e.g., screen printing systems, so long as absorbent substrates are used.
It should be understood that, as used hereinbelow, the term “concentration” is
Adams, Jr. Louis W.
West Kevin D.
Fisher George M.
Milliken & Company
Moyer Terry T.
Nerbun Peter
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