Abstract: A system and method for selective color-correction when applying three-dimensional texture to a printed substrate hinges either on a metric that is elicited from the image, or as determined by an operator. The metric may be associated with the human visual acuity curve for textural information. Other textural metrics may also be used.

Abstract: An image processing method and apparatus for generating a gray level rendered pixel value that has been subjected to a halftoning process. In the method and apparatus a gray level pixel value of the pixel to be rendered by the halftoning process is provided as one input to a lookup table. A coordinate value that is determined from a pixel location in the image of the pixel to be rendered by the halftoning process is also provided as a second input to the lookup table. The first and second inputs represent an address in the lookup table of a rendered halftone value for halftone rendering of the pixel having the input gray value and the pixel location in the image.

Abstract: Forming a multicolor image on a receiver member wherein a database of custom color profiles based on substrate physical properties and printing process characteristics is established. A set of universal color profiles is determined based on physical properties of substrates from clustered custom profiles. One universal color profile is assigned to a target substrate from the set of universal color profiles based on objective or subjective feedback. Thereafter, a multicolor toner image is formed on the receiver member with toners of at least three different colors of toner pigments which form various combinations of colors at different pixel locations on the receiver member to form the multicolor toner image thereon using the assigned one color profile. Based on objective or subjective feedback, the selected one universal color profile is modified, or a different universal color profile is selected.

Abstract: A color image control system and method are provided for improving the image control of printing systems, including digital front-end processors, color printers and post-finishing system. This color image control system incorporate a graininess correction including measurement and calibration using measurements of a graininess magnitude.

Abstract: A color electrostatographic printer apparatus applies respective color separation toner images to a receiver member to form a color image. A fuser assembly fuses the color image. A clear toner overcoat is then applied to the fused color toner image using a generic inverse mask that is based on receiver member characteristic. Enhanced glossing of the image is provided by a belt glosser that also improves color gamut. A generic color profile that is based on receiver member characteristics is provided to ensure color accuracy.

Abstract: A method for color correction of an image having an insignia portion in a multi-module printer (10). A first color profile is calibrated for a four-color image. A second color profile is calibrated for a four-color image with a transparent toner layer on top of the insignia portion of the four-color image. The image data is then buffered in a color input band buffer (40) and processed through the first (50) and second (60) color profiles in a color management module. The processed image data is stored in an output band buffer (70, 80) corresponding to the image data processed through each color profile. Clear toner input band data stored in a clear toner input band buffer (30) is compared with the processed image data in each output band buffer (70, 80) to select an output signal (100) on a per pixel basis to send to the multi-module printer (10).

Abstract: A method for calibrating a printer including a light-emitting diode (LED) printhead for non-uniformity on an image plane. The LED recording elements are arranged in a plurality of arrays. A plurality of characteristics (102, 104, 106, 108, 110) associated with each recording element are measured and from the measured characteristics a plurality of parameters (112, 114, 116, 118, 120) associated with each recording element is determined. Adjustment factors for a plurality of parameters are combined mathematically to determine an adjusted power density (122) for each recording element on the image plane. Correction factors (130) are then assigned to each recording element to correct for the adjusted power density (122). The correction factors (130) are stored in a memory (132) associated with the LED printhead.

Abstract: An input image capture device, capable of sampling the color density and gloss of the fused printed image (thus not requiring the printing of density patches on a separate calibration page), may compare the printed image's color density and gloss to a predicted value. Then, appearance control may be achieved by changing fuser parameters (such as fuser nip width, fuser roller temperature and the like) and other electrophotographic element control parameters (such as exposure, off-set development voltage, charger voltage and the like) to maintain a desirable constant appearance (density, gloss, etc.) of images consistently in print engine usage (within a print run and between print runs), even if different media substrates are used on the same print job. Therefore, no waste calibration sheet is needed, and a print job operator may receive more timely feedback relating to the current printing job stream.

Abstract: A color electrostatographic printer apparatus applies respective color separation toner images to a receiver member to form a color image. A fuser station fuses, or at least tacks, the color image to the receiver. A clear toner overcoat is then applied to the fused color toner image using an inverse mask, and enhanced glossing of the image is provided by a belt glosser to improve color gamut.

Abstract: An image processing method and apparatus for generating a gray level rendered pixel value that has been subjected to a halftoning process. In the method and apparatus a gray level pixel value of the pixel to be rendered by the halftoning process is provided as one input to a lookup table. A coordinate value that is determined from a pixel location in the image of the pixel to be rendered by the halftoning process is also provided as a second input to the lookup table. The first and second inputs represent an address in the lookup table of a rendered halftone value for halftone rendering of the pixel having the input gray value and the pixel location in the image.

Abstract: A method and apparatus for processing gray level image data. Gray level image data is subjected to plural separate halftone screen processing to form plural separate halftone processed screen gray level image data. The current pixel is also analyzed for contrast index. In response to analysis of the contrast index blending coefficients for processing of the halftone screen modified image data is made. The respective halftone outputs of the screen processings are multiplied by the respective blending coefficient. The resulting blended halftone gray value of the current pixel as well as neighboring pixels are then subjected to a threshold criterion test to determine if this represents a substantially binary image file such as might occur in a saturated text image file. The blended halftone gray value data for the current pixel is subjected to gray level edge enhancement processing to replace certain binary pixels adjacent an edge to reduce anti-aliasing effects.

Abstract: An edge enhancement processing system and method for modifying image data at certain pixel locations to include gray scale image data so as to reduce jaggedness in the image. An adjustable threshold device establishes a binary pixel value for an incoming current gray level pixel in accordance with a thresholding criterion. An operator accessible input to the thresholding device is used by the operator to adjust the threshold value in the thresholding criterion. A current binary pixel formed in accordance with the thresholding criterion and neighboring pixels also so formed in accordance with the thresholding criterion are examined in accordance with predetermined criteria for determining adjustment of the current pixel to a gray scale value to reduce edge jaggedness of the image. Generally, adjustment of the thresholding value is made in instances where under color removal and/or gray component replacement is employed.

Abstract: A product and process for an LED printhead used in electrophotographic printing that generates an exposure clock on the printhead for the LEDs. The present invention provides a high-speed interface that transmits print data that has been modified, or corrected, using the corresponding unique printhead brightness data as the base reference source data to the printhead boards. The corrected print data is then applied to the LED drivers that expose each LED simultaneously and uniquely. A non-linear clock is applied to the LED drivers as the reference clock to create the unique LED on time circuit. An Exposure RAM stores the data as parallel 8-bit data. A LATCH code received at an ASIC converts the Exposure RAM data into a serial bit stream. The preferred embodiment employs a 60 MHz clock, however, it should be readily apparent that numerous other clocking speeds can be employed.

Abstract: In a color electrostatographic printer apparatus having a plurality of tandem stations for applying respective color separation toner images to a receiver member, and a clear toner station for providing a clear toner overcoat to a multicolor toner image formed by the respective color separation toner images on the receiver member, a controller is provided that selectively controls deposition of clear toner to the multicolor toner image so that greater amounts of clear toner are deposited in image areas of the multicolor toner image having relatively higher density color and relatively lesser amounts of clear toner, including no clear toner, are deposited upon image areas of the multicolor toner image having relatively lower density color.

Abstract: Increasing the linearity of elements within a printhead by applying a coarse electronic adjustment to rearrange the electronic printing of data into the proper pixel line and then applying a fine electronic adjustment to reduce the bow error to fraction of a pixel line. Delays of exposure control signals are used by the fine electronic adjustment to correct linearity by a fraction of a pixel line. The delays can be repeated to multiply the number of delays available and increase the linearity resolution. The delays can also be averaged between odd and even rows of elements to increase apparent resolution.

Abstract: Correcting pixel inaccuracies in a writing device having a linear array elements wherein a mechanism to control temperature within a predetermined portion of the writing device is used to correct placement inaccuracies by first determining the inaccuracies with respect to a centering element reference point, and then adjusting the temperature within the predetermined portion of the writing device.

Abstract: A method and apparatus for correcting pixel inaccuracies in a writing device having a linear array elements wherein a mechanism to control temperature within a predetermined portion of the writing device is used to correct placement inaccuracies by first determining the inaccuracies with respect to a reference point and then adjusting the temperature within the predetermined portion of the writing device.

Abstract: A copier or a printer 10 includes a controller 16/30 with a rendering algorithm that groups sets of adjacent pixels into sets of adjacent cells where each cell corresponds to a halftone dot of an image. The algorithm operates in conjunction with a gray scale printhead 22. In sending data to the printhead, the controller 16 parses a scanned image and set the exposure for each pixel in accordance with a growth and density program. The algorithm selectively grows halftone dots from zero size to a desired size equal to or less than a maximum size. It repeats this step for the rest of the pixels until the cell is at its desired size and at an initial density. If a higher density is desired, the algorithm selectively adjusts the fully grown cells by sequentially increasing the level of exposure of each pixel in the cell. The image is developed with developer including a hard magnetic carrier and toner.

Abstract: A method and apparatus for increasing the linearity of elements within a printhead by applying a coarse electronic adjustment to rearrange the electronic printing of data into the proper pixel line and then applying a fine electronic adjustment to reduce the bow error to fraction of a pixel line. Delays of exposure control signals are used by the fine electronic adjustment to correct linearity by a fraction of a pixel line. The delays can be repeated to multiply the number of delays available and increase the linearity resolution. The delays can also be averaged between odd and even rows of elements to increase apparent resolution. The first embodiment employs digital circuitry to provide the fine adjustment of pixel data that is partially located on the interface board and partially located on the printhead substrate. This reduces the amount of circuitry placed within the ASICs on the printhead substrate.

Abstract: A product and process for an LED printhead used in electrophotographic printing that generates an exposure clock on the printhead for the LEDs. The present invention provides a high-speed interface that transmits print data that has been modified, or corrected, using the corresponding unique printhead brightness data as the base reference source data to the printhead boards. The corrected print data is then applied to the LED drivers that expose each LED simultaneously and uniquely. A non-linear clock is applied to the LED drivers as the reference clock to create the unique LED on time circuit. An Exposure RAM stores the data as parallel 8-bit data. A LATCH code received at an ASIC converts the Exposure RAM data into a serial bit stream. The preferred embodiment employs a 60 MHz clock, however, it should be readily apparent that numerous other clocking speeds can be employed.