Facsimile and static presentation processing – Static presentation processing – Attribute control
Reexamination Certificate
1999-04-23
2002-02-26
Popovici, Dov (Department: 2622)
Facsimile and static presentation processing
Static presentation processing
Attribute control
C358S001160, C358S518000
Reexamination Certificate
active
06351320
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to color printing, and more particularly to a memory-saving printer driver along with a color printer and printing system including same.
BACKGROUND OF THE INVENTION
Liquid ink printers of the type frequently referred to as continuous stream or as drop-on-demand, such as piezoelectric, acoustic, phase change wax-based or thermal, have at least one printhead from which droplets of ink are directed towards a recording sheet. Within the printhead, the ink is contained in a plurality of channels. Power pulses cause the droplets of ink to be expelled as required from orifices or nozzles at the end of the channels.
In a thermal ink-jet printer, the power pulses are usually produced by resistors, each located in a respective one of the channels, which are individually addressable to heat and vaporize ink in the channels. As voltage is applied across a selected resistor, a vapor bubble grows in the associated channel and initially bulges from the channel orifice followed by collapse of the bubble. The ink within the channel then retracts and separates from the bulging ink thereby forming a droplet moving in a direction away from the channel orifice and towards the recording medium whereupon hitting the recording medium a dot or spot of ink is deposited. The channel is then refilled by capillary action, which, in turn, draws ink from a supply container of liquid ink. Operation of a thermal ink-jet printer is described in, for example, U.S. Pat. No. 4,849,774.
The ink jet printhead may be incorporated into either a carriage type printer, a partial width array type printer, or a page-width type printer. The carriage type printer typically has a relatively small printhead containing the ink channels and nozzles. The printhead can be sealingly attached to a disposable ink supply cartridge and the combined printhead and cartridge assembly is attached to a carriage which is reciprocated to print one swath of information (equal to the length of a column of nozzles), at a time, on a stationary recording medium, such as paper or a transparency. After the swath is printed, the paper is stepped a distance equal to the height of the printed swath or a portion thereof, so that the next printed swath is contiguous or overlapping therewith. This procedure is repeated until the entire page is printed. In contrast, the page width printer includes a stationary printhead having a length sufficient to print across the width or length of a sheet of recording medium at a time. The recording medium is continually moved past the page width printhead in a direction substantially normal to the printhead length and at a constant or varying speed during the printing process. A page width ink-jet printer is described, for instance, in U.S. Pat. No. 5,192,959.
Printers typically print color and/or monochrome images received from an image output device such as a personal computer, a scanner, or a workstation. The color images printed are produced by printing with several colored inks or colorants of different colors at a time. The color of the ink and amount of ink deposited by the printer is determined according to image information received from a document creator such as a scanner or a computer workstation. The document creator provides an image defined in colorimetric terms, typically digital in nature R, G, B. Commonly this description may be part of a Page Description Language (PDL) file describing the document. In the case of computer generated images, colors defined by the user at a user interface of a workstation can be defined initially in a color space of tristimulus values. These colors are defined independently of any particular device, and accordingly reference is made to the information as being “device independent”.
The printer, on the other hand, often has an output which can be defined as existing in a color space called CMYK (cyan-magenta-yellow-key or black) which is uniquely defined for the printer by its capabilities and colorants as well as the media upon which the printer deposits ink. Printers operate by the addition of overlapping multiple layers of ink or colorant in layers to a page or by the adjacent deposition of colorants. The response of the printer tends to be relatively non-linear. These colors are defined for a particular device, and accordingly reference is made to the information as being “device dependent”. Thus, while a printer receives information in a device independent color space, the information must be converted to print in a device dependent color space, which reflects a possible range of colors of the printer, and secondly, printing of that image with a color printer in accordance with the colors defined by the scanner or computer generated image.
The perceived color of the image is determined not only by the relative amounts of each colorant put down on the recording medium, but also by the order in which the colorants are printed and the media type. Consequently, there are a multitude of variables which affects a final printed image. To accurately reproduce an original image, therefore, requires a transformation from a device independent color space to a multitude of device dependent color spaces, each one being determined, at least in part by, the combined effects of colorant, image density, media type, and print speed.
Various color printing systems and methods for printing color images on a recording medium are illustrated and described in the following disclosures which may be relevant to certain aspects of the present invention.
U.S. Pat. No. 4,275,413 to Sakamoto et al. describes a linear interpolating method and apparatus for color signals in a memory of a picture reproducing machine such as a color scanner, a color facsimile producer, or the like. The linear interpolating method for signals in the memory is used for color correction of pictures in the reproducing machine.
U.S. Pat. No. 5,664,072 to Ueda et al. describes a color conversion device wherein color value data including data for outputting color images inputted to a CPU. A color conversion means may preferably convert the set of input-color data into the set of print control data, while correcting the distortion in the uniform color space in regards to human visual sense.
“Digital Computation of Dot Areas in a Colour Scanner”, pages 93-96, Korman and Yule, Proceedings of the Eleventh International Conference of Printing Research Institute, Canandaigua, N.Y., 1971, describes a method of computing the dot areas required for accurate colour reproduction suitable for use in a color scanner with a digital computer.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a memory-saving printer driver for controlling output image aspects and quality in a color printer. The memory-saving printer driver itself includes a User Interface segment having a graphical display for selecting output image aspects. The graphical display includes a media type portion for selecting a desired one of a first plural number “M” of different media types for printing an output image thereon, and a lookup table segment storing a second plural number “N” of media-type basis color correction lookup tables for making color corrections on output images to be printed on each media type selected from the media portion. Each media-type basis color correction lookup table of the second plural number “N” is mapped for making corrections on each of a third plural and variable number “K” of different media types of the first plural number “M”, wherein “K” is one of a series of subsets of the first plural number “M”, thereby resulting in the second plural number “N” being less than the first plural number “M”, and in significant savings in lookup table storage memory.
In accordance with another aspect of the present invention, there is provided a color printer including a printhead for printing color images on a selected medium from the plurality of different media types, and memory-saving printer driver for controlling output image aspects
Ngutt Tallam I.
Popovici Dov
Xerox Corporation
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