Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2001-08-22
2004-09-14
Nerbun, Peter (Department: 3765)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C345S604000, C347S015000
Reexamination Certificate
active
06792329
ABSTRACT:
This disclosure relates to a computer-assisted process for the design and placement of multi-colored patterns on absorbent substrates using a limited number of transparent process colorants. Specifically, this disclosure relates to a process by which a designer, working with a computer-aided design system, can generate and accurately represent on a computer monitor or similar display a multi-colored pattern, as that pattern would appear on a specified absorbent substrate, using coloring elements comprised of groups of multiple pixels in which process colorants have been mixed in a controlled manner to expand the range of available colors, and to compensate for colorant delivery limitations that prevent the application of small, accurately metered quantities of colorant. In an embodiment 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
Of the various methods that may be used to apply a pattern of colorants (e.g., dyes) to a textile web, arguably the most versatile method involves the pixel-wise application of measured quantities of liquid colorants, under the control of a computer containing a patterning program, to form multi-colored patterns using a predetermined set of primary or process colors. Examples of such pattern generation techniques may be found in commonly assigned U.S. Pat. Nos. 4,033,154; 4,116,626; 4,545,086; 4,984,169, and 5,195,043, hereby incorporated by reference herein.
Although the teachings herein are not limited to such machines, the machines embodying the patterning techniques described in the above-listed patent documents are particularly well-adapted for patterning webs of textile substrates. Such machines are characterized by a series of fixed, linear arrays or “color bars” comprised of a plurality of individually controllable liquid colorant applicators or jets, each array being supplied by a respective liquid colorant supply system carrying liquid colorant (a “process colorant”) of a specified color (known as a “process” color). The arrays are positioned in parallel relationship, spanning the width of the path taken by the substrate to be patterned, and the arrays are generally perpendicular to the direction of web travel.
As the substrate moves along its 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 or color bar. The control system associated with the machine provides for the capability of delivering a precise quantity of dye or other liquid colorant (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.
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) in a given pass can be no greater than the number of arrays. Additionally, due to the physical limitations associated with the individual liquid dye applicators, there is some non-zero minimum quantity of colorant that can be accurately and repeatedly metered onto the substrate, typically representing the limit as to how quickly the valves controlling colorant delivery can be made to turn on and off. This becomes an important issue when the pattern color to be reproduced requires a combination of process colors having a relatively low proportion of a certain colorant (e.g., “Colorant A”), and the patterning system cannot deliver Colorant A to that specific pattern location except in an amount that significantly exceeds the quantity needed. These two conditions—a limited number of process colorants and a minimum colorant delivery system—represent limitations to the range of colors that can be represented on the substrate. Unless specifically stated otherwise, the terms “dye” and “colorant” shall be used interchangeably herein to indicate a liquid colorant that is intended to include, but is not necessarily limited to, textile dyes.
A recurring challenge associated with such devices having a limited number of process colorants is devising ways to allow for the reproduction of the widest possible range of colors (i.e., reproducing the maximum number of different target colors) from a given set of conditions, i.e., the given set of process colorants and the minimum colorant delivery limitation. Among the techniques used in the graphics arts industry to extend the range of reproduced colors from a limited number of process colors (which, in the patterning devices discussed above, correspond to the number of arrays or color bars) are two techniques that shall be referred to herein as (1) dithering and halftoning techniques and (2) in situ bending techniques.
Briefly, dithering and halftoning techniques involve the use of pixels (pattern elements), usually of varying colors, that are arranged in checkerboard-like patterns to simulate, when viewed at a distance, the appearance of colors that are not represented by process colorants. For example, various shades of gray may be constructed by a checkerboard of small black and white print dots of different relative sizes. Where necessary for clarity, this discussion will distinguish dithering techniques, which are sometimes associated only with pattern areas in which the color is non-uniform, from halftone techniques, useful in pattern areas in which a continuous or uniform color is desired. In the latter, a group of pixels (i.e., a superpixel) that collectively expresses the proper color is tiled, as a repeating unit, into the appropriate pattern areas. In situ blending techniques, as used herein, involve the physical mixing of colorants within individual pixels or groups of pixels (i.e., superpixels) to generate colors that are not represented by process colorants.
Traditional dithering and halftoning techniques are based upon the phenomenon that a target color for which no exact match is available among the process colors can be visually approximated, often to a high degree of accuracy, by the juxtaposition of several individual pixels, each having a color that expresses a visual component of the desired or target color. When viewed at an appropriate distance, the eye tends to visually integrate or blend the individual contribution of each pixel in this group of adjacent pixels and provides the perception of the target color that, in reality, has been “constructed” from a mosaic of individual component colors (additive color mixing). However, note that even in traditional printing systems new colors are produced when print dots overlap. In addition, as further elaborated below, colorants in neighboring pixels mix together in some print systems. In the latter case, the individual pixels create a new color (subtractive color mixing) that can be spatially uniform.
An in situ blend shall refer to the color of the physical combination of two or more colorants that occupy at least portions of the same pixel-sized location on a substrate, as viewed at the individual pixel level. The additional colorants might have been applied to that pixel by the patterning device, or the additional colorant(s) might have migrated from an adjacent pixel. Accordingly, if the color green is to be reproduced in a given area and only yellow and blue colorants are available as process colors, the designer may (providing the patterning device is capable) elect to deliver, in a specified sequence, a predetermined quantity of yellow and a predetermined (and not necessarily equal) quantity of blue to each pixel in that area, to form the desired color green in each of the pixels comprising that area, rather than constructing the green using halftone (“checkerboarding”
Adams, Jr. Louis W.
Magee Ronald
Fisher George M.
Milliken & Company
Moyer Terry T.
Nerbun Peter
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